Python中手动写判断电话号码

#判断是不是电话号码

def checkPhone(str):
    if len(str) !=11:
        return False
    elif str[0]!="1":
        return False
    #elif str

    for i in str:
        if i>="0" or i<="9":
            return True

    return False
print(checkPhone("13135354568"))
print(checkPhone("23135354568"))