python 入门基础知识练习

1编写第一个程序,目前使用的都是python 3

# print('hello world!')

2.查看当前python编辑器的版本号

# python -v

3.使用变量

# message = 'hello world!'

# print(message)

4.字符串

name = 'jetty'

print(name.title()) #Jetty 首字母大写

print(name) # jetty

name.upper() #JEETY 转大写

name.lower() #jetty 转小写

5.合并拼接字符串

first_name = 'hongzhu'

last_name = 'zhan'

full_name = last_name +" "+ first_name

print(full_name) # zhan hongzhu

6.使用制表来添加空白

language = 'python\nJavascript\nC\nRust'

print(language)

# 打印

python

Javascript

C

Rust

7.删除空白

_blank = ' python '

print(_blank.rstrip()) #去除右侧空白

print(_blank.strip()) #去除两侧空白

print(_blank.lstrip()) #去除左侧空白

8.变量类型

num = 2.340

print(int(num)) # 整型 2

print(float(num)) # 浮点型 2.34

9.列表

color = ['red','green','yellow','pink']

# 访问元素

print(color[0]) #red

# 修改

color[0] = 'black'

# 添加元素

color.append('orange')

# 插入元素

color.insert(0,'blue') 插到第一位

print(color)

# 删除元素

del color[0] #删除当前元素

color.pop() # 删除数组最后一个元素

color.remove('red') # 删除红色

10 组织列表

排序列表

num_list = [1,2,3,4,2,1,3,1,2]

num_list.sort()

print(num_list) #[1, 1, 1, 2, 2, 2, 3, 3, 4]

临时排序

num_list = [1,2,3,4,2,1,3,1,2]

print(sorted(num_list)) #[1, 1, 1, 2, 2, 2, 3, 3, 4]

reverse 反序

num_list = [1,2,3,4,2,1,3,1,2]

num_list.reverse()

print(num_list) #[2, 1, 3, 1, 2, 4, 3, 2, 1]

列表的长度

num_list = [1,2,3,4,2,1,3,1,2]

print(len(num_list)) # 9

11 遍历列表

num_list = [1,2,3,4,2,1,3,1,2]

for i in num_list:

print(i,end=" ") # 一行显示

12.使用函数遍历

num_list = [1,2,3,4,2,1,3,1,2]

for i in range(len(num_list)):

print(num_list[i],end=" ")

13.乘方运算

squares = []

for i in range(1,6):

squares.append(i**2)

print(squares) #[1, 4, 9, 16, 25]

14.内置函数

num_list = [1,2,3,4,2,1,3,1,2]

print(max(num_list)) #4

print(min(num_list)) #1

print(sum(num_list)) #19

15.列表解析

squeres = [value**2 for value in range(1,11)]

print(squeres) #[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

16.练习示例

16.1 1-50奇数的和

odd_number =[]

for i in range(1,11,2):

odd_number.append(i)

print(sum(odd_number))

16.2 3-90 3的倍数

three_nmu = []

for i in range(3, 91):

if (i % 3==0):

three_nmu.append(i)

print(three_nmu)

16.3 1-10 的立方

squares = []

for i in range(3,11):

squares.append(i**3)

print(squares)

16.4 1-10 的立方列表解析

squares = [i**3 for i in range(3,11)]

print(squares)

17 列表切片

num_list = [1,2,3,4,2,1,3,1,2]

print(num_list[0:5]) #[1, 2, 3, 4, 2] 从第一个开始取值到第五位

print(num_list[:5]) #[1, 2, 3, 4, 2] 默认会从第一个开始取值

print(num_list[5:]) #[1, 3, 1, 2] 取后面的4位

18 元组

dimensions = (100,300)

print(dimensions[0]) #100

for i in dimensions:

print(i) #100 300

19 if 语句

num_list = [1, 2, 3, 4, 2, 1, 3, 1, 2]

for i in num_list:

if i == 2:

print(i)

20 !=

num_list = [1, 2, 3, 4, 2, 1, 3, 1, 2]

for i in num_list:

if i != 2:

print(i)

21 and

num_list = [1, 2, 3, 4, 2, 1, 3, 1, 2]

for i in num_list:

if i >=1 and i <=2:

print(i)

22 字典

alien = {'color':0,'points':1}

print(alien['color']) #color

23 修改字典

alien = {'color':0,'points':1}

alien['color'] = 'red'

print(alien) #{'color': 'red', 'points': 1}

24 删除字典

alien = {'color':0,'points':1}

del alien['color']

print(alien)

25 案例练习

25.1创建两个人的字典，存储在列表，遍历列表，输出列表

people_nums1 = {'name':'jetty','name1':'jack'}

people_nums2 ={'name':'kitty','name1':'james'}

peoples = [people_nums1,people_nums2]

for i in peoples:

print(i)

26.用户输入和while循环

ipt = input('你是小黄么？1(true) or 2(false)?')

if ipt =='1':

print('是本人')

else:

print('不是本人')

27 % //运算符

print(4 % 2) # 0

print(4 // 2) # 2

28 while运算符

count = 0

arr = []

while count < 20:

for j in range(1, 100):

if j % 11 == 0:

count = count+1

arr.append(j)

print(arr)

29 函数

# 简单求和

def num_sum(arr):

result =0

for i in arr:

result =result+i

return result

print(num_sum([1,2,3,4])) #10

30 函数默认值

def num_sum(arr=[1,2,3]):

result =0

for i in arr:

result =result+i

return result

print(num_sum()) #6

31 传递任意数量的实参

def make_prize(*top):

return top

print(make_prize(1))

print(make_prize(1,2,3))

print(make_prize(1,3,4,5))

print(make_prize(1,1,1,1,1))

# 返回

(1,)

(1, 2, 3)

(1, 3, 4, 5)

(1, 1, 1, 1, 1)

32 导入函数

# 随机数

import random

print(random.randint(1,19))

33 类

class Dog():

def __init__(self,name,age):

self.name =name

self.age = age

def sit(self):

print(self.name+''+self.age)

dog = Dog('jeety',24)

print(dog.name)

34 类 汽车里程表

class Car():

def __init__(self,make,model,year):

self.make = make

self.model = model

self.year = year

def getCarName(self):

print(self.model)

car = Car('audi','ad4',2016)

print(car.make)

35 子类方法 __init__()

class Car():

def __init__(self,name):

self.name = name

class Elastic(Car):

def __init__(self, name):

super().__init__(name)

myTesla = Elastic('tesla')

print(myTesla.name)

36 class实例

class Car():

def __init__(self,make,name,color):

self.make = make

self.name = name

self.color = color

def getCarName(self):

print('获取车的名字为'+self.name+'获取汽车的颜色'+self.color)

class Batery():

def __init__(self,batery='60'):

self.batery = batery

def discribe_batery(self):

print('This car has'+str(self.batery)+'batery')

class Elatrity(Batery):

def __init__(self, batery):

super().__init__(batery)

self.batery = Batery()

elatrity = Elatrity('100')

print(elatrity.discribe_batery())

37 文件和异常

f = open('file.txt',mode="w",encoding='utf-8')

print(f)

f.write('叫我詹躲躲\n')

f.write('叫我詹躲躲1\n')

f.close()

38 存储数据

将数据存入json文件

import json

numbers = [1,2,23,3,4,5,6,7,87]

filename = 'numbers.json'

with open(filename,'w') as f_obj:

json.dump(numbers,f_obj)

39 保存和读取用户生成的数据

import json

username = input('存储输入的数据')

filename = 'numbers.json'

with open(filename,'w') as f_obj:

json.dump(username,f_obj)

40 读取用户输入的信息

import json

filename = 'numbers.json'

with open(filename) as f_obj:

username = json.load(f_obj)

print('Welcome back',username)

41 输入和合并数据

import json

filename = 'numbers.json'

try:

with open(filename) as f_obj:

username = json.load(f_obj)

except FileNotFoundError:

username = input('存储输入的数据')

with open(filename,'w') as f_obj:

json.dump(username,f_obj)

else:

print('Welcome back',username)

42 封装成为一个函数

import json

def get_username():

filename = 'numbers.json'

try:

with open(filename) as f_obj:

username = json.load(f_obj)

except FileNotFoundError:

return None

else:

return username

def get_greeting():

username = get_username()

if username:

print('Welcome back',username)

else:

username = input('存储输入的数据')

filename = 'numbers.json'

with open(filename,'w') as f_obj:

json.dump(username,f_obj)

print('Welcome back',username)

get_greeting()