Python 2.6+ str.format()和正则表达式

name = "John"
age = 30
result = "My name is {} and I am {} years old.".format(name, age)
print(result)

My name is John and I am 30 years old.

import re

def is_number(s):
    return bool(re.match(r'^\d+$', s))

print(is_number("12345"))  # True
print(is_number("abc123"))  # False