来源丨萝卜大杂烩

作者丨周萝卜

字符串作为平时使用最多的数据类型，其常用的操作我们还是很有必要熟记于心的，本文整理了多种字符串的操作的案例，还是非常用心，记得点赞收藏~

字符串切片操作

test = "Python Programming"
print("String: ", test)# First one character
first_character = test[:1]
print("First Character: ", first_character)# Last one character
last_character = test[-1:]
print("Last Character: ", last_character)# Everything except the first one character
except_first = test[1:]
print("Except First Char.: ", except_first)# Everything except the last one character
except_last = test[:-1]
print("Except First Char.: ", except_last)# Everything between first and last two character
between_two = test[2:-2]
print("Between two character: ", between_two)# Skip one character
skip_one = test[0:18:2]  # [start:stop:step]
print("Skip one character: ", skip_one)# Reverse String
reverse_str = test[::-1]
print("Reverse String: ", reverse_str)

Output:

String:  Python ProgrammingFirst Character:  PLast Character:  gExcept First Char.:  ython ProgrammingExcept First Char.:  Python ProgramminBetween two character:  thon ProgrammiSkip one character:  Pto rgamnReverse String:  gnimmargorP nohtyP

检查字符串是否为空

import re
from collections import Countersentence = 'Canada is located in the northern part of North America'
# Example I
counter = len(re.findall("a", sentence))
print(counter)# Example II
counter = sentence.count('a')
print(counter)# Example III
counter = Counter(sentence)
print(counter['a'])

Output:

EmptyEmptyEmpty

计算字符串中字符出现次数的多种方法

import re
from collections import Countersentence = 'Canada is located in the northern part of North America'
# Example I
counter = len(re.findall("a", sentence))
print(counter)# Example II
counter = sentence.count('a')
print(counter)# Example III
counter = Counter(sentence)
print(counter['a'])

Output:

6
6
6

将 String 变量转换为 float、int 或 boolean

# String to Float
float_string = "254.2511"
print(type(float_string))string_to_float = float(float_string)
print(type(string_to_float))# String to Integer
int_string = "254"
print(type(int_string))string_to_int = int(int_string)
print(type(string_to_int))# String to Boolean
bool_string = "True"
print(type(bool_string))string_to_bool = bool(bool_string)
print(type(string_to_bool))

Output:

class 'str'class 'float>class 'str'class 'int'class 'str'class 'bool'

向字符串填充或添加零的不同方法

num = 7print('{0:0>5d}'.format(num))  # left
print('{0:0<5d}'.format(num))  # rightprint('{:05d}'.format(num))print("%0*d" % (5, num))
print(format(num, "05d"))temp = 'test'
print(temp.rjust(10, '0'))
print(temp.ljust(10, '0'))

Output:

0000770000000070000700007000000testtest000000

去掉字符串中的 space 字符

string_var = "  \t a string example\n\t\r  "
print(string_var)string_var = string_var.lstrip()  # trim white space from left
print(string_var)string_var = "  \t a string example\t  "
string_var = string_var.rstrip()  # trim white space from right
print(string_var)string_var = "  \t a string example\t  "
string_var = string_var.strip()  # trim white space from both side
print(string_var)

Output:

a string examplea string examplea string examplea string example

生成N个字符的随机字符串

import string
import randomdef string_generator(size):chars = string.ascii_uppercase + string.ascii_lowercasereturn ''.join(random.choice(chars) for _ in range(size))def string_num_generator(size):chars = string.ascii_lowercase + string.digitsreturn ''.join(random.choice(chars) for _ in range(size))# Random String
test = string_generator(10)
print(test)# Random String and Number
test = string_num_generator(15)
print(test)

Output:

acpPTojXetqmpah72cjb83eqd

以不同的方式反转字符串

test_string = 'Python Programming'string_reversed = test_string[-1::-1]
print(string_reversed)string_reversed = test_string[::-1]
print(string_reversed)# String reverse logically
def string_reverse(text):r_text = ''index = len(text) - 1while index >= 0:r_text += text[index]index -= 1return r_textprint(string_reverse(test_string))

Output:

gnimmargorP nohtyPgnimmargorP nohtyPgnimmargorP nohtyP

将 Camel Case 转换为 Snake Case 并更改给定字符串中特定字符的大小写

import redef convert(oldstring):s1 = re.sub('(.)([A-Z][a-z]+)', r'\1_\2', oldstring)return re.sub('([a-z0-9])([A-Z])', r'\1_\2', s1).lower()# Camel Case to Snake Case
print(convert('CamelCase'))
print(convert('CamelCamelCase'))
print(convert('getHTTPResponseCode'))
print(convert('get2HTTPResponseCode'))# Change Case of a particular character
text = "python programming"
result = text[:1].upper() + text[1:7].lower() \+ text[7:8].upper() + text[8:].lower()
print(result)text = "Kilometer"
print(text.lower())old_string = "hello python"
new_string = old_string.capitalize()
print(new_string)old_string = "Hello Python"
new_string = old_string.swapcase()
print(new_string)

Output:

camel_casecamel_camel_caseget_http_response_codeget2_http_response_codePython ProgrammingkilometerHello pythonhELLO pYTHON

检查给定的字符串是否是 Python 中的回文字符串

import reContinue = 1
Quit = 2def main():choice = 0while choice != Quit:# Display the menu.display_menu()# Constant to assume string is Palindromeis_palindrome = True# Get the user's choice.choice = int(input('\nEnter your choice: '))# Perform the selected action.if choice == Continue:line = input("\nEnter a string: ")str_lower = re.sub("[^a-z0-9]", "", line.lower())for i in range(0, len(str_lower)//2):if str_lower[i] != str_lower[len(str_lower) - i - 1]:is_palindrome = Falseif is_palindrome:print(line, "is a palindrome")else:print(line, "is not a palindrome")else:print('Thank You.')def display_menu():print('\n*******MENU*******')print('1) Continue')print('2) Quit')main()

Output:

*******MENU*******1) Continue2) QuitEnter your choice: 1Enter a string: A dog! A panic in a pagoda!A dog! A panic in a pagoda! is a palindrome*******MENU*******1) Continue2) QuitEnter your choice: 1Enter a string: CivicCivic is a palindrome*******MENU*******1) Continue2) QuitEnter your choice: 1Enter a string: Python vs JavaPython vs Java is not a palindrome*******MENU*******1) Continue2) QuitEnter your choice: 2Thank You.

检查字符串是否以列表中的一个字符串结尾

str_list = ['aaa', 'bbb', 'ccc', 'ddd']  # list of items
str_test = 'testccc'  # string need to testfor str_item in str_list:if str_test.endswith(str_item):print("found")break   # loop ends when result foundelse:print("not found")

Output:

not foundnot foundfound

在字符串中应用查找模式

import res1 = 'abccba'
s2 = 'abcabc'
s3 = 'canadajapanuaeuaejapancanada'
p = '123321'def match(s, p):nr = {}regex = []for c in p:if c not in nr:regex.append('(.+)')nr[c] = len(nr) + 1else:regex.append('\\%d' % nr[c])return bool(re.match(''.join(regex) + '$', s))print(match(s1, p))
print(match(s2, p))
print(match(s3, p))

Output:

True
False
True

如果是 Python 中的反斜杠，则删除最后一个字符

x = 'Canada\\'
print(x.rstrip('\\'))

Output:

Canada

在Python中拆分字符串而不丢失拆分字符

import re
string = 'canada-japan-india'print(re.split(r'(\-)', string))

Output:

['canada', '-', 'japan', '-', 'india']

从字符串 Python 中提取大写和小写字符

string = "asdfHRbySFss"uppers = [l for l in string if l.isupper()]
print (''.join(uppers))lowers = [l for l in string if l.islower()]
print (''.join(lowers))

Output:

HRSF
asdfbyss

如何在 Python 中比较字符串的索引是否相等

myString = 'AAABBB'
for idx, char in enumerate(myString, ):if idx + 1 == len(myString):breakif char == myString[idx + 1]:print(idx, char, myString[idx + 1])

Output:

0 A A
1 A A
3 B B
4 B B

在每个第 4 个字符上添加空格

string = 'Test5412Test8745Test'
print([string[i:i + 4] for i in range(0, len(string), 4)])

Output:

['Test', '5412', 'Test', '8745', 'Test']

在 Python 中以多行方式连接字符串

str1 = "This is a demo string"
str2 = "This is another  demo string"
strz = ("This is a line\n" +str1 + "\n" +"This is line 2\n" +str2 + "\n" +"This is line 3\n")print(strz)

Output:

This is a line
This is a demo string
This is line 2
This is another  demo string
This is line 3

在 Python 中将多个变量附加到列表中

volumeA = 100
volumeB = 20
volumeC = 10vol1 = []
vol2 = []vol1.extend((volumeA, volumeB, volumeC))
vol2 += [val for name, val in globals().items() if name.startswith('volume')]print(vol1)
print(vol2)

Output:

[100, 20, 10]
[100, 20, 10]

将字符串拆分为 Python 中的字符列表

s = 'canada'
l = list(s)
print(l)

Output:

['c', 'a', 'n', 'a', 'd', 'a']

如何在 Python 中小写字符串

text = ['Canada', 'JAPAN']text = [txt.lower() for txt in text]
print(text)

Output:

['canada', 'japan']

通过多个标点符号分割字符串

import re
s = 'a,b,c d!e.f\ncanada\tjapan&germany'l = re.split('[?.,\n\t&! ]', s)for i in l:print(i)

Output:

a
b
c
d
e
f
canada
japan
germany

Python 字符串填充

lines_of_text = [(123, 5487, 'Testing', 'Billy', 'Jones'),(12345, 100, 'Test', 'John M', 'Smith')
]for mytuple in lines_of_text:name = '{}, {}'.format(mytuple[4], mytuple[3])value = '$' + str(mytuple[1])print('{name:<20} {id:>8} {test:<12} {value:>8}'.format(name=name, id=mytuple[0], test=mytuple[2], value=value))

Output:

Jones, Billy              123 Testing         $5487
Smith, John M           12345 Test             $100

在 Python 中检查两个字符串是否包含相同的字符

str1 = 'caars'
str2 = 'rats'
str3 = 'racs'print(set(str1)==set(str2))
print(set(str1)==set(str3))

Output:

False
True

在 Python 中查找给定字符串中的整个单词

def contains_word(s, w):return (' ' + w + ' ') in (' ' + s + ' ')result = contains_word('those who seek shall find', 'find')
print(result)
result = contains_word('those who seek shall find', 'finds')
print(result)

Output:

True
False

查找所有出现的子字符串

import reaString = 'this is a string where the substring "is" is repeated several times'
print([(a.start(), a.end()) for a in list(re.finditer('is', aString))])

Output:

[(2, 4), (5, 7), (38, 40), (42, 44)]

在 Python 中去除所有开头在Python中的正斜杠上拆分字符串和结尾标点符号

from string import punctuation
s = '.$958-5-Canada,#'print(s.strip(punctuation))

Output:

958-5-Canada

用 Python 中的正斜杠上拆分字符串

s = 'canada/japan/australia'
l = s.split('/')print(l)

Output:

['canada', 'japan', 'australia']

根据 Python 中的索引位置将字符串大写

def capitalize(s, ind):split_s = list(s)for i in ind:try:split_s[i] = split_s[i].upper()except IndexError:print('Index out of range : ', i)return "".join(split_s)print(capitalize("abracadabra", [2, 6, 9, 10, 50]))

Output:

Index out of range :  50
abRacaDabRA

检查字符串中的所有字符是否都是Python中的数字

a = "1000"
x = a.isdigit()
print(x)b = "A1000"
x = b.isdigit()
print(x)

Output:

True
False

为什么使用'=='或'is'比较字符串有时会产生不同的结果

a = 'canada'
b = ''.join(['ca', 'na', 'da'])
print(a == b)
print(a is b)a = [1, 2, 3]
b = [1, 2, 3]
print(a == b)
print(a is b)c = b
print(c is b)

Output:

True
False
True
False
True

如何在 Python 中为字符串添加 X 个空格

print('canada'.ljust(10) + 'india'.ljust(20) + 'japan')

Output:

canada    india               japan

如何在Python中替换字符串中的特定字符串实例

def nth_replace(str,search,repl,index):split = str.split(search,index+1)if len(split)<=index+1:return strreturn search.join(split[:-1])+repl+split[-1]str1 = "caars caars caars"
str2 = nth_replace(str1, 'aa', 'a', 1)print(str2)

Output:

caars cars caars

如何连接两个变量，一个是字符串，另一个是 Python 中的 int

int1 = 10
str1 = 'test'print(str(int1) + str1)

Output:

10test

在 Python 中的反斜杠上拆分字符串

s = r'canada\japan\australia'
l = s.split('\\')print(l)

Output:

['canada', 'japan', 'australia']

在Python中随机大写字符串中的字母

from random import choicex = "canada japan australia"
print(''.join(choice((str.upper, str.lower))(c) for c in x))

Output:

CANaDA JaPan auStRALIa

在单词处拆分字符串并且或不保留分隔符

import restring = "Canada AND Japan NOT Audi OR BMW"l = re.split(r'(AND|OR|NOT)', string)
print(l)

Output:

['Canada ', 'AND', ' Japan ', 'NOT', ' Audi ', 'OR', ' BMW']

在 Python 中填充 n 个字符

def header(txt: str, width=30, filler='*', align='c'):assert align in 'lcr'return {'l': txt.ljust, 'c': txt.center, 'r': txt.rjust}[align](width, filler)print(header("Canada"))
print(header("Canada", align='l'))
print(header("Canada", align='r'))

Output:

************Canada************
Canada************************
************************Canada

检查变量是否等于一个字符串或另一个字符串

x = 'canada'if x in ['canada', 'japan', 'germany', 'australia']:print("Yes")

Output:

true

Python字符串格式化固定宽度

num1 = 0.04154721841
num2 = 10.04154721841
num3 = 1002.04154721841print "{0:<12.11g}".format(num1)[:12]
print "{0:<12.11g}".format(num2)[:12]
print "{0:<12.11g}".format(num3)[:12]

Output:

100.041549
0.04159874
12.8878877

在Python中查找字符串中字符的所有位置

test = 'canada#japan#uae'
c = '#'
print([pos for pos, char in enumerate(test) if char == c])

Output:

[6, 12]

在Python中从左右修剪指定数量的空格

def trim(text, num_of_leading, num_of_trailing):text = list(text)for i in range(num_of_leading):if text[i] == " ":text[i] = ""else:breakfor i in range(1, num_of_trailing+1):if text[-i] == " ":text[-i] = ""else:breakreturn ''.join(text)txt1 = "   Candada     "
print(trim(txt1, 1, 1))
print(trim(txt1, 2, 3))
print(trim(txt1, 6, 8))

Output:

Candada    Candada
Candada

在Python中按字符串中字符的位置拆分字符串

str = 'canadajapan'
splitat = 6
l, r = str[:splitat], str[splitat:]
print(l)
print(r)

Output:

canada
japan

将Python字符串中的第一个和最后一个字母大写

string = "canada"result = string[0:1].upper() + string[1:-1].lower() + string[-1:].upper()
print(result)

Output:

CanadA

检查字符串是否以Python中的给定字符串或字符结尾

txt = "Canada is a great country"x = txt.endswith("country")print(x)

Output:

True

如何在 Python 中比较两个字符串

str1 = "Canada"
str2 = "Canada"
print(str1 is str2)  # True
print(str1 == str2)  # Truestring1 = ''.join(['Ca', 'na', 'da'])
string2 = ''.join(['Can', 'ada'])
print(string1 is string2)  # False
print(string1 == string2)  # True

Output:

True
True
False
True

在Python中将整数格式化为带有前导零的字符串

x = 4
x = str(x).zfill(5)
print(x)

Output:

00004

在Python中替换字符串的多个子字符串

s = "The quick brown fox jumps over the lazy dog"
for r in (("brown", "red"), ("lazy", "quick")):s = s.replace(*r)print(s)

Output:

The quick red fox jumps over the quick dog

Python字符串替换字符

s = "The quick brown fox jumps over the lazy dog"
for r in (("brown", "red"), ("lazy", "quick")):s = s.replace(*r)print(s)

Output:

The quick red fox jumps over the quick dog

在Python中查找字符串中所有出现的单词的所有索引

import resentence = 'this is a sentence this this'
word = 'this'for match in re.finditer(word, sentence):print(match.start(), match.end())

Output:

0 4
19 23
24 28

在 Python 中将字符串中每个单词的首字母大写

import stringx = "they're bill's friends from the UK"
x = string.capwords(x)
print(x)x = x.title()
print(x)

Output:

They're Bill's Friends From The Uk
They'Re Bill'S Friends From The Uk

仅在 Python 中的双引号后拆分字符串

s = '"Canada", "Japan", "Germany", "Russia"'
l = ['"{}"'.format(s) for s in s.split('"') if s not in ('', ', ')]for item in l:print(item)

Output:

"Canada"
"Japan"
"Germany"
"Russia"

在 Python 中以字节为单位获取字符串的大小

string1 = "Canada"
print(len(string1.encode('utf-16')))

Output:

10

在 Python 中比较字符串中的字符

myString = 'AAABBB'
for idx, char in enumerate(myString, ):if idx + 1 == len(myString):breakif char == myString[idx + 1]:print(idx, char, myString[idx + 1])

Output:

0 A A
1 A A
3 B B
4 B B

在 Python 中的括号和字符串之间添加空格

import retest = "example(test)"
test2 = "example(test)example"
test3 = "(test)example"
test4 = "example (test) example"for i in [test, test2, test3, test4]:print(re.sub(r"[^\S]?(\(.*?\))[^\S]?", r" \1 ", i).strip())

Output:

example (test)
example (test) example
(test) example
example (test) example

在 Python 中删除开头和结尾空格

s = '   canada   '
print(s.strip())

Output:

canada

在 Python 中拆分字符串以获得第一个值

s = 'canada-japan-australia'
l = s.split('-')[0]
print(l)string = 'canada-japan-australia'
print(string[:string.index('-')])

Output:

canada
canada

在 Python 中检查字符串是大写、小写还是混合大小写

words = ['The', 'quick', 'BROWN', 'Fox','jumped', 'OVER', 'the', 'Lazy', 'DOG']print([word for word in words if word.islower()])print([word for word in words if word.isupper()])print([word for word in words if not word.islower() and not word.isupper()])

Output:

['quick', 'jumped', 'the']
['BROWN', 'OVER', 'DOG']
['The', 'Fox', 'Lazy']

Python计数字符串出现在给定字符串中

txt = "I love Canada, Canada is one of the most impressive countries in the world. Canada is a great country."x = txt.count("Canada")print(x)

Output:

3

在 Python3 中用前导零填充字符串

hour = 4
minute = 3print("{:0>2}:{:0>2}".format(hour, minute))
print("{:0>3}:{:0>5}".format(hour, minute))
print("{:0<3}:{:0<5}".format(hour, minute))
print("{:$<3}:{:#<5}".format(hour, minute))

Output:

04:03
004:00003
400:30000
4$$:3####

在 Python 中检查两个字符串是否包含相同的字母和数字

from string import ascii_letters, digitsdef compare_alphanumeric(first, second):for character in first:if character in ascii_letters + digits and character not in second:return Falsereturn Truestr1 = 'ABCD'
str2 = 'ACDB'
print(compare_alphanumeric(str1, str2))str1 = 'A45BCD'
str2 = 'ACD59894B'
print(compare_alphanumeric(str1, str2))str1 = 'A45BCD'
str2 = 'XYZ9887'
print(compare_alphanumeric(str1, str2))

Output:

True
True
False

在Python中的字符串中的字符之间添加空格的有效方法

s = "CANADA"print(" ".join(s))
print("-".join(s))
print(s.replace("", " ")[1: -1])

Output:

C A N A D A
C-A-N-A-D-A
C A N A D A

在Python中查找字符串中最后一次出现的子字符串的索引

s = 'What is Canada famous for?'print(s.find('f'))
print(s.index('f'))
print(s.rindex('f'))
print(s.rfind('f'))

Output:

15
15
22
22

在 Python 中将字符串大写

x = 'canada'
x = x.capitalize()print(x)

Output:

Canada

拆分非字母数字并在 Python 中保留分隔符

import res = "65&Can-Jap#Ind^UK"
l = re.split('([^a-zA-Z0-9])', s)
print(l)

Output:

['65', '&', 'Can', '-', 'Jap', '#', 'Ind', '^', 'UK']

计算Python中字符串中大写和小写字符的数量

string = "asdfHRbySFss"uppers = [l for l in string if l.isupper()]
print(len(uppers))lowers = [l for l in string if l.islower()]
print(len(lowers))

Output:

4
8

在 Python 中将字符串与枚举进行比较

from enum import Enum, autoclass Signal(Enum):red = auto()green = auto()orange = auto()def equals(self, string):return self.name == stringbrain_detected_colour = "red"
print(Signal.red.equals(brain_detected_colour))brain_detected_colour = "pink"
print(Signal.red.equals(brain_detected_colour))

Output:

True
False

Python中的段落格式

import textwraphamlet = '''\
Lorum ipsum is the traditional Latin placeholder text, used when a designer needs a chunk of text for dummying up a layout.
Journo Ipsum is like that, only using some of the most common catchphrases, buzzwords, and bon mots of the future-of-news crowd.
Hit reload for a new batch. For entertainment purposes only.'''wrapper = textwrap.TextWrapper(initial_indent='\t' * 1,subsequent_indent='\t' * 2,width=40)for para in hamlet.splitlines():print(wrapper.fill(para))

Output:

Lorum ipsum is the traditional Latinplaceholder text, used when a designerneeds a chunk of text for dummying upa layout.Journo Ipsum is like that, only usingsome of the most common catchphrases,buzzwords, and bon mots of the future-of-news crowd.Hit reload for a new batch. Forentertainment purposes only.

从 Python 中的某个索引替换字符

def nth_replace(str,search,repl,index):split = str.split(search,index+1)if len(split)<=index+1:return strreturn search.join(split[:-1])+repl+split[-1]str1 = "caars caars caars"
str2 = nth_replace(str1, 'aa', 'a', 1)print(str2)

Output:

caars cars caars

如何连接 str 和 int 对象

i = 123
a = "foobar"
s = a + str(i)
print(s)

Output:

foobar123

仅在 Python 中将字符串拆分为两部分

s = 'canada japan australia'
l = s.split(' ', 1)
print(l)

Output:

['canada', 'japan australia']

将大写字符串转换为句子大小写

text = ['CANADA', 'JAPAN']text = [txt.capitalize() for txt in text]
print(text)

Output:

['Canada', 'Japan']

在标点符号上拆分字符串

string = 'a,b,c d!e.f\ncanada\tjapan&germany'
identifiers = '!"#$%&\'()*+,-./:;<=>?@[\\]^_`{|}~\n\t 'listitems = "".join((' ' if c in identifiers else c for c in string)).split()for item in listitems:print(item)

Output:

a
b
c
d
e
f
canada
japan
germany

在 Python 中比较字符串

str1 = "Canada"
str2 = "Canada"
print(str1 is str2)  # True
print(str1 == str2)  # Truestring1 = ''.join(['Ca', 'na', 'da'])
string2 = ''.join(['Can', 'ada'])
print(string1 is string2)  # False
print(string1 == string2)  # True

Output:

True
True
False
True

用零填充数字字符串

num = 123
print('{:<08d}'.format(num))
print('{:>08d}'.format(num))string = '123'
print(string.ljust(8, '0'))
print(string.rjust(8, '0'))print(string[::-1].zfill(8)[::-1])

Output:

12300000
00000123
12300000
00000123
12300000

找到两个字符串之间的差异位置

def dif(a, b):return [i for i in range(len(a)) if a[i] != b[i]]print(dif('stackoverflow', 'stacklavaflow'))

Output:

[5, 6, 7, 8]

Python填充字符串到固定长度

number = 4print(f'{number:05d}')  # (since Python 3.6), or
print('{:05d}'.format(number))  # orprint('{0:05d}'.format(number))
print('{n:05d}'.format(n=number))  # or (explicit `n` keyword arg. selection)
print(format(number, '05d'))

Output:

00004
00004
00004
00004
00004
00004

Python中的字符串查找示例

import retext = 'This is sample text to test if this pythonic '\'program can serve as an indexing platform for '\'finding words in a paragraph. It can give '\'values as to where the word is located with the '\'different examples as stated'find_the_word = re.finditer('as', text)for match in find_the_word:print('start {}, end {}, search string \'{}\''.format(match.start(), match.end(), match.group()))

Output:

start 63, end 65, search string 'as'
start 140, end 142, search string 'as'
start 200, end 202, search string 'as'

删除字符串中的开头零和结尾零

list_num = ['000231512-n', '1209123100000-n00000','alphanumeric0000', '000alphanumeric']print([item.strip('0') for item in list_num])   # Remove leading + trailing '0'
print([item.lstrip('0') for item in list_num])  # Remove leading '0'
print([item.rstrip('0') for item in list_num])  # Remove trailing '0'

Output:

['231512-n', '1209123100000-n', 'alphanumeric', 'alphanumeric']
['231512-n', '1209123100000-n00000', 'alphanumeric0000', 'alphanumeric']
['000231512-n', '1209123100000-n', 'alphanumeric', '000alphanumeric']

Python在换行符上拆分

s = 'line 1\nline 2\nline without newline'
l = s.splitlines(True)print(l)

Output:

['line 1\n', 'line 2\n', 'line without newline']

将字符串中的每个第二个字母大写

s = 'canada'
s = "".join([x.upper() if i % 2 != 0 else x for i, x in enumerate(s)])print(s)

Output:

cAnAdA

在 Python 中查找一个月的最后一个营业日或工作日

import calendardef last_business_day_in_month(year: int, month: int) -> int:return max(calendar.monthcalendar(year, month)[-1:][0][:5])print(last_business_day_in_month(2021, 1))
print(last_business_day_in_month(2021, 2))
print(last_business_day_in_month(2021, 3))
print(last_business_day_in_month(2021, 4))
print(last_business_day_in_month(2021, 5))

Output:

29
26
31
30
31

比较两个字符串中的单个字符

def compare_strings(a, b):result = Trueif len(a) != len(b):print('string lengths do not match!')for i, (x, y) in enumerate(zip(a, b)):if x != y:print(f'char miss-match {x, y} in element {i}')result = Falseif result:print('strings match!')return resultprint(compare_strings("canada", "japan"))

Output:

string lengths do not match!
char miss-match ('c', 'j') in element 0
char miss-match ('n', 'p') in element 2
char miss-match ('d', 'n') in element 4
False

在 Python 中多次显示字符串

print('canada' * 3)
print(*3 * ('canada',), sep='-')

Output:

canadacanadacanada
canada-canada-canada

Python从头开始替换字符串

def nth_replace(s, old, new, occurrence):li = s.rsplit(old, occurrence)return new.join(li)str1 = "caars caars caars caars caars"
str2 = nth_replace(str1, 'aa', 'a', 1)
print(str2)str2 = nth_replace(str1, 'aa', 'a', 2)
print(str2)str2 = nth_replace(str1, 'aa', 'a', 3)
print(str2)

Output:

caars caars caars caars cars
caars caars caars cars cars
caars caars cars cars cars

在 Python 中连接字符串和变量值

year = '2020'print('test' + str(year))
print('test' + year.__str__())

Output:

test2020
test2020

在每个下划线处拆分字符串并在第 N 个位置后停止

s = 'canada_japan_australia_us_uk'
l = s.split('_', 0)
print(l)l = s.split('_', 1)
print(l)l = s.split('_', 2)
print(l)

Output:

['canada_japan_australia_us_uk']
['canada', 'japan_australia_us_uk']
['canada', 'japan', 'australia_us_uk']

Python中列表中第一个单词的首字母大写

text = ['johnny rotten', 'eddie vedder', 'kurt kobain','chris cornell', 'micheal phillip jagger']text = [txt.capitalize() for txt in text]
print(text)

Output:

['Johnny rotten', 'Eddie vedder', 'Kurt kobain', 'Chris cornell', 'Micheal phillip jagger']

如何在 Python 字符串中找到第一次出现的子字符串

test = 'Position of a character'
print(test.find('of'))
print(test.find('a'))

Output:

9
12

不同长度的Python填充字符串

data = [1148, 39, 365, 6, 56524]for element in data:print("{:>5}".format(element))

Output:

1148393656
56524

Python比较两个字符串保留一端的差异

def after(s1, s2):index = s1.find(s2)if index != -1 and index + len(s2) < len(s1):return s1[index + len(s2):]else:return Nones1 = "canada"
s2 = "can"print(after(s1, s2))

Output:

ada

如何用Python中的一个字符替换字符串中的所有字符

test = 'canada'
print('$' * len(test))

Output:

$$$$$$

在字符串中查找子字符串并在 Python 中返回子字符串的索引

def find_str(s, char):index = 0if char in s:c = char[0]for ch in s:if ch == c:if s[index:index + len(char)] == char:return indexindex += 1return -1print(find_str("India Canada Japan", "Canada"))
print(find_str("India Canada Japan", "cana"))
print(find_str("India Canada Japan", "Uae"))

Output:

6
-1
-1

从 Python 中的字符串中修剪特定的开头和结尾字符

number = '+91 874854778'print(number.strip('+'))
print(number.lstrip('+91'))

Output:

91 874854778874854778

在 Python 中按长度将字符串拆分为字符串

string = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"x = 3
res = [string[y - x:y] for y in range(x, len(string) + x, x)]
print(res)

Output:

['ABC', 'DEF', 'GHI', 'JKL', 'MNO', 'PQR', 'STU', 'VWX', 'YZ']

如何在 Python 中将字符串的第三个字母大写

s = "xxxyyyzzz"# convert to list
a = list(s)# change every third letter in place with a list comprehension
a[2::3] = [x.upper() for x in a[2::3]]# back to a string
s = ''.join(a)print(s)

Output:

xxXyyYzzZ

将制表符大小设置为指定的空格数

txt = "Canada\tis\ta\tgreat\tcountry"print(txt)
print(txt.expandtabs())
print(txt.expandtabs(2))
print(txt.expandtabs(4))
print(txt.expandtabs(10))

Output:

Canada   is  a   great   country
Canada  is      a       great   country
Canada  is  a great country
Canada  is  a   great   country
Canada    is        a         great     country

将两个字符串与某些字符进行比较

str1 = "Can"
str2 = "Canada"
print(str1 in str2)
print(str1.startswith(str2))
print(str2.startswith(str1))print(str1.endswith(str2))str3 = "CAN"
print(str3 in str2)

Output:

True
False
True
False
False

字符串格式化填充负数

n = [-2, -8, 1, -10, 40]num = ["{1:0{0}d}".format(2 if x >= 0 else 3, x) for x in n]
print(num)

Output:

n = [-2, -8, 1, -10, 40]num = ["{1:0{0}d}".format(2 if x >= 0 else 3, x) for x in n]
print(num)

单独替换字符串中的第一个字符

str1 = "caars caars caars"
str2 = str1.replace('aa', 'a', 1)print(str2)

Output:

cars caars caars

连接固定字符串和变量

variable = 'Hello'
print('This is the Test File ' + variable)variable = '10'
print('This is the Test File ' + str(variable))

Output:

This is the Test File Hello
This is the Test File 10

将字符串拆分为多个字符串

s = 'str1, str2, str3, str4'
l = s.split(', ')print(l)

Output:

['str1', 'str2', 'str3', 'str4']

在 Python 中将字符串大写

x = "canada japan australia"x = x[:1].upper() + x[1:]
print(x)x= x.capitalize()
print(x)x= x.title()
print(x)

Output:

Canada japan australia
Canada japan australia
Canada Japan Australia

将字节字符串拆分为单独的字节

data = b'\x00\x00\x00\x00\x00\x00'info = [data[i:i + 2] for i in range(0, len(data), 2)]
print(info)

Output:

[b'\x00\x00', b'\x00\x00', b'\x00\x00']

用空格填写 Python 字符串

string = 'Hi'.ljust(10)
print(string)string = 'Hi'.rjust(10)
print(string)string = '{0: ^20}'.format('Hi')
print(string)string = '{message: >16}'.format(message='Hi')
print(string)string = '{message: <16}'.format(message='Hi')
print(string)string = '{message: <{width}}'.format(message='Hi', width=20)
print(string)

Output:

Hi        HiHi         Hi
Hi
Hi

比较两个字符串并检查它们共有多少个字符

from collections import Counterdef shared_chars(s1, s2):return sum((Counter(s1) & Counter(s2)).values())print(shared_chars('car', 'carts'))

Output:

3

在 Python 中的数字和字符串之间添加空格

import res = "ABC24.00XYZ58.28PQR"
s = re.sub("[A-Za-z]+", lambda group: " " + group[0] + " ", s)
print(s.strip())

Output:

ABC 24.00 XYZ 58.28 PQR

如何在 Python 中去除空格

s = '   canada  '
print(s.rstrip())  # For whitespace on the right side use rstrip.
print(s.lstrip())  # For whitespace on the left side lstrip.
print(s.strip())  # For whitespace from both side.s = ' \t  canada  '
print(s.strip('\t'))  # This will strip any space, \t, \n, or \r characters from the left-hand side, right-hand side, or both sides of the string.

Output:

canada
canada
canadacanada

字符串中最后一次出现的分隔符处拆分字符串

s = 'canada-japan-australia-uae-india'
l = s.rsplit('-', 1)[1]
print(l)

Output:

india

在Python中将字符串的最后一个字母大写

string = "canada"result = string[:-1] + string[-1].upper()
print(result)result = string[::-1].title()[::-1]
print(result)

Output:

canadA
canadA

使用指定字符居中对齐字符串

txt = "canada"x = txt.center(20)print(x)

Output:

canada

格式字符串中动态计算的零填充

x = 4
w = 5
print('{number:0{width}d}'.format(width=w, number=x))

Output:

00004

在 Python 中使用 string.replace()

a = "This is the island of istanbul"
print (a.replace("is" , "was", 1))
print (a.replace("is" , "was", 2))
print (a.replace("is" , "was"))

Output:

Thwas is the island of istanbul
Thwas was the island of istanbul
Thwas was the wasland of wastanbul

在 Python 中获取字符的位置

test = 'Position of a character'
print(test.find('of'))
print(test.find('a'))

Output:

9
12

Python字符串替换多次出现

s = "The quick brown fox jumps over the lazy dog"
for r in (("brown", "red"), ("lazy", "quick")):s = s.replace(*r)print(s)

Output:

The quick red fox jumps over the quick dog

在索引后找到第一次出现的字符

string = 'This + is + a + string'
x = string.find('+', 4)
print(x)x = string.find('+', 10)
print(x)

Output:

5
10

在 Python 中将字符串更改为大写

x = 'canada'
x = x.upper()print(x)

Output:

CANADA

在 Python 中拆分具有多个分隔符的字符串

import rel = re.split(r'[$-]+', 'canada$-india$-japan$-uae')
print(l)

Output:

['canada', 'india', 'japan', 'uae']

在 Python 中获取字符串的大小

string1 = "Canada"
print(len(string1))string2 = "  Canada"
print(len(string2))string3 = "Canada  "
print(len(string3))

Output:

6
8
8

Python中的字符串比较 is vs ==

x = 'canada'
y = ''.join(['ca', 'na', 'da'])
print(x == y)
print(x is y)x = [1, 2, 3]
y = [1, 2, 3]
print(x == y)
print(x is y)z = y
print(z is y)

Output:

True
False
True
False
True

每当数字与非数字相邻时，Python 正则表达式都会添加空格

import retext = ['123', 'abc', '4x5x6', '7.2volt', '60BTU','20v', '4*5', '24in', 'google.com-1.2', '1.2.3']pattern = r'(-?[0-9]+\.?[0-9]*)'
for data in text:print(repr(data), repr(' '.join(segment for segment in re.split(pattern, data) if segment)))

Output:

'123' '123'
'abc' 'abc'
'4x5x6' '4 x 5 x 6'
'7.2volt' '7.2 volt'
'60BTU' '60 BTU'
'20v' '20 v'
'4*5' '4 * 5'
'24in' '24 in'
'google.com-1.2' 'google.com -1.2'
'1.2.3' '1.2 . 3'

在 Python 中仅按第一个空格拆分字符串

s = 'canada japan australia'
l = s.split(' ', 1)
print(l)

Output:

['canada', 'japan australia']

在Python中将字符串中的一些小写字母更改为大写

indices = set([0, 7, 14, 18])s = "i love canada and japan"
print("".join(c.upper() if i in indices else c for i, c in enumerate(s)))

Output:

I love Canada And Japan

将字符串拆分为具有多个单词边界分隔符的单词

import rethestring = "a,b,c d!e.f\ncanada\tjapan&germany"
listitems = re.findall('\w+', thestring)for item in listitems:print(item)

Output:

a
b
c
d
e
f
canada
japan
germany

检查一个字符串在 Python 中是否具有相同的字符

str1 = 'caars'
str2 = 'rats'
str3 = 'racs'print(set(str1)==set(str2))
print(set(str1)==set(str3))

Output:

False
True

在多个分隔符或指定字符上拆分字符串

import restring_test = "Ethnic (279), Responses (3), 2016 Census - 25% Sample"
print(re.findall(r"[\w']+", string_test))def split_by_char(s, seps):res = [s]for sep in seps:s, res = res, []for seq in s:res += seq.split(sep)return resprint(split_by_char(string_test, [' ', '(', ')', ',']))

Output:

['Ethnic', '279', 'Responses', '3', '2016', 'Census', '25', 'Sample']['Ethnic', '', '279', '', '', 'Responses', '', '3', '', '', '2016', 'Census', '-', '25%', 'Sample']

将一个字符串附加到另一个字符串

# Example 1
str1 = "Can"
str2 = "ada"
str3 = str1 + str2
print(str3)# Example 2
str4 = 'Ca'
str4 += 'na'
str4 += 'da'
print(str4)# Example 3
join_str = "".join((str1, str2))
print(join_str)# Example 4
str_add = str1.__add__(str2)
print(str_add)

Output:

CanadaCanadaCanadaCanada

在 Python 中遍历字符串

# Example 1
test_str = "Canada"
for i, c in enumerate(test_str):print(i, c)print("------------------------")# Example 2
indx = 0
while indx < len(test_str):print(indx, test_str[indx])indx += 1print("------------------------")
# Example 3
for char in test_str:print(char)

Output:

0 C1 a2 n.......da

从 Python 中的字符串中去除标点符号

import string
import re# Example 1
s = "Ethnic (279), Responses (3), 2016 Census - 25% Sample"
out = re.sub(r'[^\w\s]', '', s)
print(out)# Example 2
s = "Ethnic (279), Responses (3), 2016 Census - 25% Sample"
for p in string.punctuation:s = s.replace(p, "")
print(s)# Example 3
s = "Ethnic (279), Responses (3), 2016 Census - 25% Sample"
out = re.sub('[%s]' % re.escape(string.punctuation), '', s)
print(out)

Output:

Ethnic 279 Responses 3 2016 Census  25 SampleEthnic 279 Responses 3 2016 Census  25 SampleEthnic 279 Responses 3 2016 Census  25 Sample

将列表转换为字符串

list_exp = ['Ca', 'na', 'da']
print(type(list_exp))# Example 1
str_exp1 = ''.join(list_exp)
print(type(str_exp1))
print(str_exp1)# Example 2
str_exp2 = ''.join(str(e) for e in list_exp)
print(type(str_exp2))
print(str_exp2)# Example 3
str_exp3 = ''.join(map(str, list_exp))
print(type(str_exp2))
print(str_exp2)

Output:

class 'list'class 'str'Canadaclass 'str'Canadaclass 'str'Canada

将 JSON 转换为字符串

import json# list with dict a simple Json format
json_exp = \[{"id": "12", "name": "Mark"}, {"id": "13", "name": "Rock", "date": None}]
print(type(json_exp))str_conv = json.dumps(json_exp)  # string
print(type(str_conv))
print(str_conv)

Output:

class 'list'class 'str'[{"id": "12", "name": "Mark"}, {"id": "13", "name": "Rock", "date": null}]

对字符串列表进行排序

# Example 1
str_list = ["Japan", "Canada", "Australia"]
print(str_list)
str_list.sort()
print(str_list)# Example 2
str_list = ["Japan", "Canada", "Australia"]
for x in sorted(str_list):print(x)# Example 3
str_var = "Canada"
strlist = sorted(str_var)
print(strlist)

Output:

['Japan', 'Canada', 'Australia']['Australia', 'Canada', 'Japan']AustraliaCanadaJapan['C', 'a', 'a', 'a', 'd', 'n']

在 Python 中检查字符串是否以 XXXX 开头

import reexp_str = "Python Programming"# Example 1
if re.match(r'^Python', exp_str):print(True)
else:print(False)# Example 2
result = exp_str.startswith("Python")
print(result)

Output:

TrueTrue

在 Python 中将两个字符串网格或交错在一起的不同方法

str1 = "AAAA"
str2 = "BBBBBBBBB"# Example 1
mesh = "".join(i + j for i, j in zip(str1, str2))
print("Example 1:", mesh)# Example 2
min_len = min(len(str1), len(str2))
mesh = [''] * min_len * 2
mesh[::2] = str1[:min_len]
mesh[1::2] = str2[:min_len]
print("Example 2:", ''.join(mesh))# Example 3
mesh = ''.join(''.join(item) for item in zip(str1, str2))
print("Example 3:", mesh)# Example 4
min_len = min(len(str1), len(str2))
mesh = [''] * min_len * 2
mesh[::2] = str1[:min_len]
mesh[1::2] = str2[:min_len]
mesh += str1[min_len:] + str2[min_len:]
print("Example 4:", ''.join(mesh))

Output:

Example 1: ABABABABExample 2: ABABABABExample 3: ABABABABExample 4: ABABABABBBBBB

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