CODEWITHSUNDEEP
pythonregexfilematch
Daniel Slater
Daniel Slater

Reputation: 123

python return all lines after last regex match

I bet it's an easy answer for fellow pythoners. I'm a rookie and I've been searching for an answer for quite a while now (hours)...

How to return all lines after last regex match (including and excluding match)? I'm playing with python 2.6

data:

string log 1 
string log 2
string match
string log 4
string match
string log 5
string log 6

expected case 1:

string match
string log 5
string log 6

expected case 2:

string log 5
string log 6

Same question for bash what posted here How to get all lines after a line number

sed solution: 

sed -n 'H; /string match/h; ${g;p;}'
sed -n 'H; /string match/h; ${g;p;}' | grep -v 'string match'

Upvotes: 0

Views: 5216

Answers (3)

Jerry
Jerry

Reputation: 71598

If you're looking into a shorter piece of code, maybe that?

Case 1:

>>> import re
>>> input_data = open('path/file').read()
>>> result = re.search(r'.*(string match\s*.*)$', input_data, re.DOTALL)
>>> print(result.group(1))
string match
string log 5
string log 6

Case 2:

>>> import re
>>> input_data = open('path/file').read()
>>> result = re.search(r'.*string match\s*(.*)$', input_data, re.DOTALL)
>>> print(result.group(1))
string log 5
string log 6

Warning though, there'll be a lot of backtracking in that regex if the last 'string match' is way up in the file.

Upvotes: 1

eyquem
eyquem

Reputation: 27585

t = '''string log 1 
string log 2
string match
string log 4
string match
string log 5
string log 6'''

me = t.rsplit('string match',1)[1].lstrip()

e = t[t.rfind('string match'):]

print '%s\n\n%r\n\n%r' % (t,me,e)

result

string log 1 
string log 2
string match
string log 4
string match
string log 5
string log 6

'string log 5\nstring log 6'

'string match\nstring log 5\nstring log 6'

Upvotes: 0

falsetru
falsetru

Reputation: 369494

import sys

with open('/path/to/file', 'rb') as f:
    last_pos = pos = 0
    for line in f:
        pos += len(line)
        if 'string match' in line:
            last_pos = pos
    f.seek(last_pos)
    sys.stdout.writelines(f)

Used a loop to find last match position. Then used file.seek to move file position.

Upvotes: 0

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