Replace all the occurrences of specific words

Question

Suppose that I have the following sentence:

bean likes to sell his beans

and I want to replace all occurrences of specific words with other

Answer 1

If you replace each word one at a time, you might replace words several times (and not get what you want). To avoid this, you can use a function or lambda:

d = {'bean':'robert', 'beans':'cars'}
str_in = 'bean likes to sell his beans'
str_out = re.sub(r'\b(\w+)\b', lambda m:d.get(m.group(1), m.group(1)), str_in)

That way, once bean is replaced by robert, it won't be modified again (even if robert is also in your input list of words).

As suggested by georg, I edited this answer with dict.get(key, default_value). Alternative solution (also suggested by georg):

str_out = re.sub(r'\b(%s)\b' % '|'.join(d.keys()), lambda m:d.get(m.group(1), m.group(1)), str_in)