Python helper函数

转日期类型 helper函数：

from datetime import datetime
import re

date_pattern = re.compile("^\d+-\d+-\d+$")

def str_to_date(date):
    if isinstance(date, datetime.date):
        return date
    elif isinstance(date, str) and date_pattern.match(date):
        return datetime.date(*map(int, date.split("-")))
    else:
        raise TypeError

 

转str, 转bytes helper函数：

def to_str(bytes_or_str):
    if isinstance(bytes_or_str, bytes):
        value = bytes_or_str.decode('utf-8')
    else:
        value = bytes_or_str
    return value

def to_bytes(bytes_or_str):
    if isinstance(bytes_or_str, str):
        value = bytes_or_str.encode('utf-8')
    else:
        value = bytes_or_str
    return value