如何为从我的whatsapp消息导出的日期时间编写正则表达式代码

Question

I am trying to analyse my whatsapp data, but am running into problems. Almost every example I looked at made a variable for the datetime pattern that looks like one of these:

• pattern = '^([0-9]+)(/)([0-9]+)(/)([0-9][0-9]), ([0-9]+):([0-9][0-9]) (AM|PM) -'
• pattern = '^\d{1,2}/\d{1,2}/\d{1,2}, \d{1,2}:\d{1,2}\S [AaPp][Mm] -'
• pattern = '^([0-9]+)(/)([0-9]+)(/)([0-9]+), ([0-9]+):([0-9]+)[ ]?(AM|PM|am|pm)? -'
• pattern = '\d{1,2}/\d{1,2}/\d{2,4},\s\d{1,2}:\d{2}\s-\s'

these patterns are all based on their whatsapp data which as you can see included am and pm a lot of the time. I happen to live in the Netherlands where we don't use am or pm, so I am lost on how to write the pattern code for this datetime (bold) :

(random whatsapp message below)

[31-08-2020 17:41:12] Eva Zandbergen: Dit krijgt meneer niet binnen

I have tried every line of code I could find on the internet, but none of them worked. If someone could tell me how to write the pattern code for this datetime, they would actually be my hero.

below I have added screenshots of the notebook file I am working in. Hopefully it can give some insight into my problems:

my notebook file

error 1

eror 2

Answer 1

Something like this should work:

(\[[0-3]{1}[0-9]{1}-[0-1]{1}[0-9]{1}-\d{4}\s[[0-2]{1}[0-9]{1}:[0-5]{1}[0-9]{1}:[0-5]{1}[0-9]{1}\])

I've put it in regex101.com and it pulls it out ok... also gives you the explanation of what it is doing.

It would probably be worth you running a few additional cases in the example string to ensure you dont get any rogues.

Its quite simple, and I did it quite quickly so it only handles the basic dates - it wont filter out days that months dont have that others do, but it will filter out anything over the 31st of any month, or anything over 12 months)

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Update: I've transcribed your notebook into my own and used a very small random dataset to do what your notebook is doing and it seems to extract them out ok, I've hosted this on github here: https://github.com/danstreeter/stackoverflow-70643023

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Another thought on this, but if you know the inbound data is well formatted, and will always be well formatted - which you may be able to expect from something like a WhatsApp message export: is rather than looking for dates by regex, just slice each message string as an array and getting the 1st to 21st characters:

with open('gezin.txt', 'r') as opened_file:
    for line in opened_file:
        print(line[0:21])

Obviously this is very dependant on the data being well formed, and the date ALWAYS appearing as the first 21 characters of each line - but a possibility if these things are true.