CODEWITHSUNDEEP
pythonregex
Boel
Boel

Reputation: 986

How should I print a string that matches this pattern in a file?

Given a file with content like this:

{
    "title": "Pilot",
    "image": [
        {
            "resource": "http://images2.nokk.nocookie.net/__cb20110227141960/notr/images/8/8b/pilot.jpg",
            "description": "not yet implemented"
        }
    ],
    "content": "<p>The pilot ...</p>"
},
{
    "title": "Special Christmas (Part 1)",
    "image": [
        {
            "resource": "http://images1.nat.nocookie.net/__cb20090519172121/obli/images/e/ed/SpecialChristmas.jpg",
            "description": "not yet implemented"
        }
    ],
    "content": "<p>Last comment...</p>"
}

I have this script to replace all the values of resource, like this,

"resource": "http://images1.nat.nocookie.net/__cb20090519172121/obli/images/e/ed/SpecialChristmas.jpg"

for another like this: "../img/SpecialChristmas.jpg"

from StringIO import StringIO    
import re
import urllib

infile = open('test2.txt')
outfile = open('test3.txt', 'w')

pattern = r'"resource": ".+/(.+).jpg"'
replacement = '"resource": "../img/\g<1>.jpg"'
prog = re.compile(".+/(.+).jpg")

for line in infile:
    if prog.match(line):
        print (line) #this prints nothing
    text = re.sub(pattern, replacement, line)
    outfile.write(text)
infile.close()
outfile.close

But I also want to print the value of every resource in the loop, like this:

"http://images1.nat.nocookie.net/__cb20090519172121/obli/images/e/ed/SpecialChristmas.jpg"
"http://images1.nat.nocookie.net/__cb20090519172121/obli/images/e/ed/SpecialChristmas.jpg"

What I'm doing doesn't work, so what would be the right way to print every resource value just in console?

Thanks in advance!

Upvotes: 1

Views: 125

Answers (3)

rtrwalker
rtrwalker

Reputation: 1021

You can have groups within groups and just modify your original pattern regex. This can get a bit confusing so it is easier to use named groups ie. (?P<group_name>pattern)

import re
import urllib

infile = open('test2.txt')
outfile = open('test3.txt', 'w')

pattern = r'"resource": "(?P<path>.+/(?P<filename>.+)\.jpg)"'
replacement = '"resource": "../img/\g<filename>.jpg"'
prog = re.compile(pattern)

for line in infile:
    match = prog.match(line)
    if match:
        print (match.group('path'))
    text = prog.sub(replacement, line)
    outfile.write(text)
infile.close()
outfile.close

Upvotes: 1

kojiro
kojiro

Reputation: 77197

from json import dumps, loads
with open('that_file') as datfile:
  dat = loads('[' + datfile.read() + ']') # Need some outer braces to make it valid JSON
for item in dat:
  for img in item['image']:
    if 'resource' in img:
      # You may want to do a more sophisticated test here
      # but this will do for an example
      img['resource'] = 'http://example.org'
with open('that_file', 'w') as datfile:
  datfile.write(dumps(dat, indent=4).strip('[]')) # Strip outer array braces in keeping with input. (Shrug)

Upvotes: 2

Boel
Boel

Reputation: 986

I ended up doing this:

from StringIO import StringIO    
import re
import urllib

infile = open('test2.txt')
outfile = open('test4.txt', 'w')

pattern = r'"resource": ".+/(.+).jpg"'
replacement = '"resource": "../img/\g<1>.jpg"'
prog = re.compile(pattern)

for line in infile:
    if prog.search(line):
        url = line.split('"resource":')[1][2:][:-3]
        print(url)
    text = re.sub(pattern, replacement, line)
    outfile.write(text)
infile.close()
outfile.close

it works but I think it doesn't look pythonic at all

Upvotes: 0

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