Given a string and we have to check whether it contains only digits or not in Python.

给定一个字符串，我们必须检查它在Python中是否仅包含数字。

To check that a string contains only digits (or a string has a number) – we can use isdigit() function, it returns true, if all characters of the string are digits.

要检查字符串是否仅包含数字 (或字符串包含数字 )，可以使用isdigit()函数 ，如果字符串的所有字符均为数字，则返回true 。

Syntax:

句法：

    string.isdigit()

Example:

例：

    Input:
str1 = "8789"
str2 = "Hello123"
str3 = "123Hello"
str4 = "123 456" #contains space
# function call
str1.isdigit()
str2.isdigit()
str3.isdigit()
str4.isdigit()
Output:
True
False
False
False

Python code to check whether a strings contains a number or not

检查字符串是否包含数字的Python代码

# python program to check whether a string
# contains only digits or not
# variables declaration & initializations
str1 = "8789"
str2 = "Hello123"
str3 = "123Hello"
str4 = "123 456"    #contains space
# checking
print("str1.isdigit(): ", str1.isdigit())
print("str2.isdigit(): ", str2.isdigit())
print("str3.isdigit(): ", str3.isdigit())
print("str4.isdigit(): ", str4.isdigit())
# checking & printing messages
if str1.isdigit():
print("str1 contains a number")
else:
print("str1 does not contain a number")
if str2.isdigit():
print("str2 contains a number")
else:
print("str2 does not contain a number")
if str3.isdigit():
print("str3 contains a number")
else:
print("str3 does not contain a number")
if str4.isdigit():
print("str4 contains a number")
else:
print("str4 does not contain a number")

Output

输出量

str1.isdigit():  True
str2.isdigit():  False
str3.isdigit():  False
str4.isdigit():  False
str1 contains a number
str2 does not contain a number
str3 does not contain a number
str4 does not contain a number

翻译自: https://www.includehelp.com/python/check-whether-a-string-contains-a-number-or-not.aspx