python自定义isnumber函数判断字符串是否为数字
''' isnumeric.py test a numeric string s if it's usable for int(s) or float(s) ''' def isnumeric(s): '''returns True if string s is numeric''' return all(c in "0123456789.+-" for c in s) # test module ... if __name__ == '__main__': print(isnumeric('123')) # True print(isnumeric('-123.45')) # True print(isnumeric('+3.14')) # True print(isnumeric('$99.95')) # False