如何为 Python 做 PHP 的 strtotime 函数

Question

First: Sorry my bad english ok? Second: I already looked at this post python - strtotime equivalent?

So, i'm trying to use the function strtotime('+{amount} days or minutes') in Python. This function is PHP, but in Python how to do?

I'm using Django

I'm doing this def :

import time, re

def strtotime(string):
  try:
    now = int(time.time())
    amount = int(re.sub('[^0-9]', '', string))

    if 'minute' in string:
      return now + (amount * 60)
    elif 'hour' in string:
      return now + (amount * 3600)
    elif 'day' in string:
      return now + (amount * 86400)
    elif 'week' in string:
      return now + (amount * 604800)
    elif 'year' in string:
      return now + (amount * (365 * 86400) + 86400)
    else:
      return now + amount
  except:
    return False

Answer 1

First, I'd recommend looking into simply using dateparser as they have implemented similar functionality: https://dateparser.readthedocs.io/en/latest/

---

But, for the sake of completeness, let's also make your function work for your provided use-case. Namely, the "{num} minute|hour|day|week|year" example. I assume you'd want to chain these as well, so this works for things like 1 year 3 days 5 minutes .

import time, re


def strtotime(string):
    unit_to_second = dict(
        minute=60, hour=3600, day=86400, week=604800, year=(365 * 86400) + 86400
    )
    accumulator = time.time()

    for match in re.finditer(r"([0-9]) (minute|hour|day|week|year)", string):
        num, unit = match.groups()
        accumulator += float(num) * unit_to_second[unit]

    return accumulator

This uses a dict to avoid all the if / elif branches. It uses a regex with grouping to iterate through all {num} {timeunit} patterns of the string, and adds the corresponding length of time to an accumulator which is initialized as the current time, giving us the offset.

Here are examples (formatted to see what it does):

import datetime

print(datetime.datetime.fromtimestamp(time.time()))
# ==> 2019-12-10 09:41:16.328347

example = strtotime("1 day")
print(datetime.datetime.fromtimestamp(example))
# ==> 2019-12-11 09:41:16.328403

example = strtotime("2 days 5 hours")
print(datetime.datetime.fromtimestamp(example))
# ==> 2019-12-12 14:41:16.328686

example = strtotime("1 week 3 days 2 minutes")
print(datetime.datetime.fromtimestamp(example))
# ==> 2019-12-20 09:43:16.328705