How to display the first few characters of a string in Python?


Question

Hi I just started learning Python but I'm sort of stuck right now.

I have hash.txt file containing thousands of malware hashes in MD5, Sha1 and Sha5 respectively separated by delimiters in each line. Below are 2 examples lines I extracted from the .txt file.

416d76b8811b0ddae2fdad8f4721ddbe|d4f656ee006e248f2f3a8a93a8aec5868788b927|12a5f648928f8e0b5376d2cc07de8e4cbf9f7ccbadb97d898373f85f0a75c47f 56a99a4205a4d6cab2dcae414a5670fd|612aeeeaa8aa432a7b96202847169ecae56b07ee|d17de7ca4c8f24ff49314f0f342dbe9243b10e9f3558c6193e2fd6bccb1be6d2

My intention is to display the first 32 characters (MD5 hash) so the output will look something like this:

416d76b8811b0ddae2fdad8f4721ddbe 56a99a4205a4d6cab2dcae414a5670fd

Any ideas?

1
76
7/30/2012 9:47:50 AM

Accepted Answer

You can 'slice' a string very easily, just like you'd pull items from a list:

a_string = 'This is a string'

To get the first 4 letters:

first_four_letters = a_string[:4]
>>> 'This'

Or the last 5:

last_five_letters = a_string[-5:]
>>> 'string'

So applying that logic to your problem:

the_string = '416d76b8811b0ddae2fdad8f4721ddbe|d4f656ee006e248f2f3a8a93a8aec5868788b927|12a5f648928f8e0b5376d2cc07de8e4cbf9f7ccbadb97d898373f85f0a75c47f '
first_32_chars = the_string[:32]
>>> 416d76b8811b0ddae2fdad8f4721ddbe
161
12/19/2014 4:46:13 PM

Since there is a delimiter, you should use that instead of worrying about how long the md5 is.

>>> s = "416d76b8811b0ddae2fdad8f4721ddbe|d4f656ee006e248f2f3a8a93a8aec5868788b927|12a5f648928f8e0b5376d2cc07de8e4cbf9f7ccbadb97d898373f85f0a75c47f"
>>> md5sum, delim, rest = s.partition('|')
>>> md5sum
'416d76b8811b0ddae2fdad8f4721ddbe'

Alternatively

>>> md5sum, sha1sum, sha5sum = s.split('|')
>>> md5sum
'416d76b8811b0ddae2fdad8f4721ddbe'
>>> sha1sum
'd4f656ee006e248f2f3a8a93a8aec5868788b927'
>>> sha5sum
'12a5f648928f8e0b5376d2cc07de8e4cbf9f7ccbadb97d898373f85f0a75c47f'

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