string replace using a list with a for loop

Question

I am new to python and I want to replace characters in a string with with characters from a list for example.

tagFinder = ['<', '>','&']
safeTag = ['&lt;','&gt','&amp']

for i in content:
    return content.replace(tagFinder[i],safeTag[i]

I keep getting the following error

TypeError: list indices must be integers, not str

could someone please help a brother out thanks in advance!

Abhijit · Accepted Answer · 2015-04-26 10:12:49Z

3

You probably intended

for i in range(len(tagFinder)):
    content = content.replace(tagFinder[i],safeTag[i])
..........
return content

instead of

for i in content:
    return content.replace(tagFinder[i],safeTag[i])

and also you are prematurely exiting the loop because of the return statement. The return statement should be the last statement in your function, assuming these statements are in a function

but then it is always better to use the built-in zip here

for src, dest in zip(tagFinder , safeTag ):
    content = content.replace(src, dest)
..........
return content

but then, unless this is part of a homework, you should use the standard library to escape your html string. In this particular case, cgi will be useful.

>>> import cgi
>>> cgi.escape(data).encode('ascii', 'xmlcharrefreplace')
'&lt;&gt;&amp;'

edited Apr 26, 2015 at 10:12

answered Apr 26, 2015 at 9:53

Abhijit

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6 Comments

NubmcNub Over a year ago

TypeError: 'int' object is not iterable - i get that as an error?

Abhijit Over a year ago

@NubmcNub: My bad. I have corrected the typographical error

NubmcNub Over a year ago

thanks im almost there but when i return it i get this Expected :'<p>Hello World</p>' Actual :'&amplt;p&ampgtHello World&amplt;/p&ampgt'

NubmcNub Over a year ago

do i hae to escape the '&'?

Abhijit Over a year ago

Change the order of your tags such that tagFinder = ['&', '<', '>'] and safeTag = ['&amp', '<','&gt']

|

bosnjak · Accepted Answer · 2015-04-26 09:54:35Z

0

If you insist in doing it manually:

tagFinder = ['<', '>','&']
safeTag = ['&lt;','&gt','&amp']

for tag, safe in zip(tagFinder, safeTag):
    content = content.replace(tag, safe)

But there is a better way to escape HTML characters in Python:

import cgi
content = cgi.escape(content)

answered Apr 26, 2015 at 9:54

bosnjak

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