RegEx for matching URLs and failing non-URLs

Question

I am trying to extract separated urls from srcset of an image.

This is for extracting and downloading all the files present in the row. I am not hard coding it because row can differ from time to time.

txt = "images/1x/1083bce6__color_272x92dp.png 1x, images/2x/b3716cd2_color_272x92dp.png 2x"

reg = re.compile(r"((?:[^\s,]+))(?:.*?,)?").finditer

for i in list(reg(txt)):
   print(i.group(1))

I expect the result to be two urls

images/1x/1083bce6__color_272x92dp.png
images/2x/b3716cd2_color_272x92dp.png

But I get three with extra being

2x

Answer 1

Here, we would add a quantifier to a simple char class in an expression such as:

[^\s]{4,}

to get our desired URLs.

Demo

Test

# coding=utf8
# the above tag defines encoding for this document and is for Python 2.x compatibility

import re

regex = r"[^\s]{4,}"

test_str = "images/1x/1083bce6__color_272x92dp.png 1x, images/2x/b3716cd2_color_272x92dp.png 2x"

matches = re.finditer(regex, test_str, re.MULTILINE)

for matchNum, match in enumerate(matches, start=1):
    
    print ("Match {matchNum} was found at {start}-{end}: {match}".format(matchNum = matchNum, start = match.start(), end = match.end(), match = match.group()))
    
    for groupNum in range(0, len(match.groups())):
        groupNum = groupNum + 1
        
        print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = match.start(groupNum), end = match.end(groupNum), group = match.group(groupNum)))

# Note: for Python 2.7 compatibility, use ur"" to prefix the regex and u"" to prefix the test string and substitution.

RegEx

If this expression wasn't desired, it can be modified/changed in regex101.com.

RegEx Circuit

jex.im visualizes regular expressions: