python -regular expression - list element

[antar2]

Hello,

I am a beginner in Python and am not able to use a list element for
regular expression, substitutions.

list1 = [ 'a', 'o' ]
list2 = ['star', 'day', 'work', 'hello']

Suppose that I want to substitute the vowels from list2 that are in
list1, into for example 'u'.
In my substitution, I should use the elements in list1 as a variable.
I thought about:

for x in list1:
re.compile(x)
for y in list2:
re.compile(y)
if x in y:
z = re.sub(x, 'u', y)
but this does not work

 

[cokofreedom]

Hello,

I am a beginner in Python and am not able to use a list element for
regular expression, substitutions.

list1 = [ 'a', 'o' ]
list2 = ['star', 'day', 'work', 'hello']

Suppose that I want to substitute the vowels from list2 that are in
list1, into for example 'u'.
In my substitution, I should use the elements in list1 as a variable.
I thought about:

for x in list1:
re.compile(x)
for y in list2:
re.compile(y)
if x in y:
z = re.sub(x, 'u', y)
but this does not work

I think you misunderstand the point of re.compile, it is for compiling
a regular expression.

import re
list1 = [ 'a', 'o' ]
list2 = ['star', 'day', 'work', 'hello']
for x in list1:

for y in list2:
if x in y:
print re.sub(x, 'u', y)
stur
duy
wurk
hellu

 

[Chris]

You need to frotz the hymangirator with spangule.

That, or show us the actual result you're seeing and how it differs
from what you expect to happen.

--
 \     "I must say that I find television very educational. The minute |
  `\   somebody turns it on, I go to the library and read a book."  -- |
_o__)                                                     Groucho Marx |
Ben Finney

That made me laugh

Why not a list comprehension ?

::: list1 = ['a','o']
::: list2 = ['star', 'day', 'work', 'hello']
::: [l2.replace(l1,'u') for l2 in list2 for l1 in list1 if l1 in l2]
['stur', 'duy', 'wurk', 'hellu']

 

[Matimus]

Hello,

I am a beginner in Python and am not able to use a list element for
regular expression, substitutions.

list1 = [ 'a', 'o' ]
list2 = ['star',  'day', 'work', 'hello']

Suppose that I want to substitute the vowels from list2 that are in
list1, into for example 'u'.
In my substitution, I should use the elements in list1 as a variable.
I thought about:

for x in list1:
   re.compile(x)
        for y in list2:
           re.compile(y)
                if x in y:
                        z = re.sub(x, 'u', y)
but this does not work

Others have given you several reasons why that doesn't work. Nothing I
have seen will work for words which contain both 'a' and 'o' however.
The most obvious way to do that is probably to use a re:

words = ['star', 'day', 'work', 'hello', 'halo']
vowels = [ 'a', 'o' ]
import re
vp = re.compile('|'.join(vowels))
[vp.sub('u', w) for w in words] ['stur', 'duy', 'wurk', 'hellu', 'hulu']

However, the fastest way is probably to use maketrans and translate:

from string import maketrans, translate
trans = maketrans(''.join(vowels), 'u'*len(vowels))
[translate(w, trans) for w in words]

['stur', 'duy', 'wurk', 'hellu', 'hulu']

Matt