Python string replacement

Question

I'm trying to replace the occurrence of a word with another:

word_list = { "ugh" : "disappointed"}

tmp = ['laughing ugh']

for index, data in enumerate(tmp):
    for key, value in word_list.iteritems():
        if key in data:
            tmp[index]=data.replace(key, word_list[key])

print tmp

Whereas this works... the occurrence of ugh in laughing is also being replaced in the output: ladisappointeding disappointed.

How does one avoid this so that the output is laughing disappointed?

Split the string on spaces. Only replace exact matches – OneCricketeer Feb 24 '16 at 10:16 — OneCricketeer, Feb 24 '16 at 10:16

Ian · Accepted Answer · 2016-02-24T10:25:38.247

In that case, you may want to consider to replace word by word.

Example:

word_list = { "ugh" : "disappointed"}
tmp = ['laughing ugh']

for t in tmp:
    words = t.split()
    for i in range(len(words)):
        if words[i] in word_list.keys():
            words[i] = word_list[words[i]]
    newline = " ".join(words)
    print(newline)

Output:

laughing disappointed

Step-by-Step Explanations:

Get every sentence in the tmp list:
```
for t in tmp:
```
split the sentence into words:
```
words = t.split()
```

check whether any word in words are in the word_list keys. If it does, replace it with its value:

for i in range(len(words)):
    if words[i] in word_list.keys():
        words[i] = word_list[words[i]]

rejoin the replaced words and print the result out:
```
newline = " ".join(words)
print(newline)
```

JonnyTieM · Answer 2 · 2016-02-24T10:41:44.777

4

You can do this by using a RegEx:

>>> import re
>>> re.sub(r'\bugh\b', 'disappointed', 'laughing ugh')
'laughing disappointed'

The \b stands for a word boundary.

edited Feb 24 '16 at 10:41

answered Feb 24 '16 at 10:19

JonnyTieM

177
2
12

score 2 · Answer 3 · answered Feb 24 '16 at 10:22

2

Use re.sub:

for key, value in word_list.items():
    tmp = re.sub("\\b{}\\b".format(key), value, tmp[index])

answered Feb 24 '16 at 10:22

score 2 · Answer 4 · answered Feb 24 '16 at 11:56

word_list = { "ugh" : "disappointed", "123" : "lol"}
tmp = ['laughing 123 ugh']

for word in tmp:
    words = word.split()
for i in words[:]:
    if  i in word_list.keys():
    replace_value = word_list.get(i)
    words[words.index(i)] = replace_value
output = " ".join(words)
print output

This code will swap each key of the dict (so the word you want to replace ) with the dict value of that key ( the word you want it to be replaced with) in every case and with multiple values!

Output:
    laughing lol disappointed

Hope that helps!

score 1 · Answer 5 · answered Feb 24 '16 at 10:22

You can use regular expressions:

import re

for index, data in enumerate(tmp):
    for key, value in word_list.iteritems():
        if key in data:
            pattern = '\b' + key + '\b'
            data = re.sub(pattern, value, data)
            tmp[index] = data

Side note: you need data = ... line (to overwrite data variable) otherwise it will work incorrectly when word_list contains multiple entries.

score 1 · Answer 6 · answered Feb 24 '16 at 10:45

Fast:

>>> [re.sub(r'\w+', lambda m: word_list.get(m.group(), m.group()), t) 
     for t in tmp]
['laughing disappointed']
>>>

Very Fast:

>>> [re.sub(r'\b(?:%s)\b' % '|'.join(word_list.keys()), lambda m: word_list.get(m.group(), m.group()), t) 
...  for t in tmp]
['laughing disappointed']
>>>

Python string replacement

6 Answers6