Python: Splitting a string in a list

Question

I am having trouble splitting an '&' in a list of URL's. I know it is because I cannot split a list directly but I cannot figure out how to get around this error. I am open for any suggestions.

def nestForLoop():
    lines = open("URL_leftof_qm.txt", 'r').readlines()
    for l in lines:
        toke1 = l.split("?")
        toke2 = toke1.split("&")
        for t in toke2:
            with open("ampersand_right_split.txt".format(), 'a') as f:
                    f.write
    lines.close()

nestForLoop()

Ignacio Vazquez-Abrams · Accepted Answer · 2013-10-11 22:35:57Z

8

NO. STOP.

qs = urlparse.urlparse(url).query
qsl = urlparse.parse_qsl(qs)

answered Oct 11, 2013 at 22:35

Ignacio Vazquez-Abrams

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Comments

abarnert · Accepted Answer · 2013-10-11 22:46:35Z

1

As Ignacio points out, you should not be doing this in the first place. But I'll explain where you're going wrong, and how to fix it:

toke2 is a list of two strings: the main URL before the ?, and the query string after the &. You don't want to split that list, or everything in that list; you just want to split the query string. So:

mainurl, query = l.split("?")
queryvars = query.split("&")

What if you did want to split everything in the first list? There are two different things that could mean, which are of course done differently. But both require a loop (explicit, or inside a list comprehension) over the first list. Either this:

tokens = [toke2.split("&") for toke2 in l.split("?")]

or

tokens = [token for toke2 in l.split("?")
          for token in toke2.split("&")]

Try them both out to see the different outputs, and hopefully you'll understand what they're doing.

edited Oct 11, 2013 at 22:46

answered Oct 11, 2013 at 22:41

abarnert

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4 Comments

Michael Jerzy Regdosz Over a year ago

I'm getting a Value error. Probably because there is code in my file that does not have an & on some lines. How can I fix this?

abarnert Over a year ago

Having lines without a & wouldn't raise anything, but a line without a ? would. Change the first line to mainurl, _, query = l.partition('?').

Michael Jerzy Regdosz Over a year ago

It splits on the '?' but not on the '&'.

abarnert Over a year ago

@MichaelJerzyRegdosz: If you're actually using the code I wrote above, splitting on the ? but not the & will not raise a ValueError; you'll successfully get a 1-element list in queryvars. So, either you're wrong, and it's the ? that's missing, or you wrote different code than what I showed, in which case I can't debug code that I haven't seen.

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