How to define a function that takes a string (sentence) and inserts an extra space after a period if the period is directly followed by a letter.
sent = "This is a test.Start testing!"
def normal(sent):
list_of_words = sent.split()
...
This should print out
"This is a test. Start testing!"
I suppose I should use split() to brake a string into a list, but what next?
P.S. The solution has to be as simple as possible.
Use re.sub. Your regular expression will match a period (\.) followed by a letter ([a-zA-Z]). Your replacement string will contain a reference to the second group (\2), which was the letter matched in the regular expression.
>>> import re
>>> re.sub(r'\.([a-zA-Z])', r'. \1', 'This is a test.This is a test. 4.5 balloons.')
'This is a test. This is a test. 4.5 balloons'
Note the choice of [a-zA-Z] for the regular expression. This matches just letters. We do not use \w because it would insert spaces into a decimal number.
One-liner non-regex answer:
def normal(sent):
return ".".join(" " + s if i > 0 and s[0].isalpha() else s for i, s in enumerate(sent.split(".")))
Here is a multi-line version using a similar approach. You may find it more readable.
def normal(sent):
sent = sent.split(".")
result = sent[:1]
for item in sent[1:]:
if item[0].isalpha():
item = " " + item
result.append(item)
return ".".join(result)
Using a regex is probably the better way, though.
Brute force without any checks:
>>> sent = "This is a test.Start testing!"
>>> k = sent.split('.')
>>> ". ".join(l)
'This is a test. Start testing!'
>>>
For removing spaces:
>>> sent = "This is a test. Start testing!"
>>> k = sent.split('.')
>>> l = [x.lstrip(' ') for x in k]
>>> ". ".join(l)
'This is a test. Start testing!'
>>>
Another regex-based solution, might be a tiny bit faster than Steven's (only one pattern match, and a blacklist instead of a whitelist):
import re
re.sub(r'\.([^\s])', r'. \1', some_string)
Improving pyfunc's answer:
sent="This is a test.Start testing!"
k=sent.split('.')
k='. '.join(k)
k.replace('. ','. ')
'This is a test. Start testing!'
