how to custom format on print from a regex match using python

Question

Using python, I need to extract an ID and Date from this filename:

export-foobar-54321-2015_02_18_23_30_00.csv.gz

Where: ID = 54321 Date = 2015_02_18

So far, I can match the file name with this regular expression:

export-foobar-[0-9]{5}\-[0-9]{4}_[0-9]{2}_[0-9]{2}_[0-9]{2}_[0-9]{2}_[0-9]{2}.csv.gz

What I'd like as my final print out put would be:

ID = 54321 Date =02-18-2015

Being new to python, I tried the following, however, im not sure how to print what I need. I have this so far:

>>> import re
>>> filename='export-generic-33605-2015_02_18_23_30_00.csv.gz'
>>> matches=re.search("export-foobar-[0-9]{5}\-[0-9]{4}_[0-9]{2}_[0-9]{2}_[0-9]{2}_[0-9]{2}_[0-9]{2}.csv.gz",filename)
>>> print(matches)
<_sre.SRE_Match object at 0x7f2ee3616718>

If I could please get some help in printing out what I need and then customizing the print to match the date MM-DD-YYYY correctly would be appreciated.

Avinash Raj · Accepted Answer · 2015-06-19 07:20:17Z

3

Use capturing groups and also replace foobar in your regex to generic or use [^-]+ instead of generic if you don't know the actual value.

>>> import re
>>> filename='export-generic-33605-2015_02_18_23_30_00.csv.gz'
>>> matches=re.search(r"export-generic-([0-9]{5})-([0-9]{4}_[0-9]{2}_[0-9]{2})_[0-9]{2}_[0-9]{2}_[0-9]{2}\.csv\.gz",filename).groups()
>>> Id, Date = matches
>>> Id
'33605'
>>> Date
'2015_02_18'
>>> date = re.sub(r'^([^_]+)_([^_]+)_([^_]+)$', r'\2-\3-\1', Date)
>>> date
'02-18-2015'

edited Jun 19, 2015 at 7:20

answered Jun 19, 2015 at 6:21

Avinash Raj

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Grokify · Accepted Answer · 2015-06-19 06:30:28Z

2

You can use the following to capture the digits of interest and rearrange the date. generic in your regexp was changed to \w+ to capture any text string.

filename = 'export-foobar-54321-2015_02_18_23_30_00.csv.gz'

matches=re.search(r"export-\w+-([0-9]{5})-([0-9]{4})_([0-9]{2})_([0-9]{2})_[0-9]{2}_[0-9]{2}_[0-9]{2}\.csv\.gz",filename).groups()
Id, Year, Month, Day = matches
Date = '-'.join([Month, Day, Year])

print(Id) # 54321
print(Date) # 02-18-2015

answered Jun 19, 2015 at 6:30

Grokify

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