基于Python的 如何检查字符串输入是否为数字

# 示例代码5
import re

input_str = input("请输入一个字符串: ")
pattern = r'^[0-9]+$'
if re.search(pattern, input_str):
    print("输入的字符串是数字")
else:
    print("输入的字符串不是数字")

import os
import sys
import re
from multiprocessing import Process


def test_input(fn):
    sys.stdin = os.fdopen(fn)
    while True:
        msg = sys.stdin.readline()
        pattern = r'^[0-9]+$'
        if re.search(pattern,msg):
            info = int(msg.strip('\n'))
            print(info)
            if info == 12:
                print("equel is 1")
        else:
            print("input wrong value ")



if __name__ == "__main__":
    print("start progress!")
    fn = sys.stdin.fileno()
    Process(target=test_input, args=(fn, )).start()