I am looking for the most pythonic way to replace the first and last word of a string (doing it on a letter basis won't work for various reasons). To demonstrate what I'm trying to do, here is an example.
a = "this is the demonstration sentence."
I'd like the result of my python function to be:
b = "This is the demonstration Sentence."
The tricky part of it is that there might be spaces on the front or the end of the string. I need those to be preserved.
Here's what I mean:
a = " this is a demonstration sentence. "
The result would need to be:
b = " This is a demonstration Sentence. "
Would also be interested in opinions on whether a regex would do this job better than python's inbuilt methods, or vice versa.
import re
a = " this is a demonstration sentence. "
print(re.sub(r'''(?x) # VERBOSE mode
( #
^ # start of string
\s* # zero-or-more whitespaces
\w # followed by an alphanumeric character
)
| # OR
(
\w # an alphanumeric character
\S* # zero-or-more non-space characters
\s* # zero-or-more whitespaces
$ # end of string
)
''',
lambda m: m.group().title(),
a))
yields
This is a demonstration Sentence.
Does this work for you:
In [9]: a = "this is the demonstration sentence."
In [10]: left, _, right = a.strip().partition(' ')
In [11]: mid, _, right = right.rpartition(' ')
In [12]: Left = left.title()
In [13]: Right = right.title()
In [14]: a = a.replace(left, Left, 1).replace(right, Right, 1)
In [15]: a
Out[15]: 'This is the demonstration Sentence.'
Here's a regex solution:
def cap(m):
return m.group(0).title()
re.sub(r'(?:^\s*\w+)|(?:[^\s]+\s*$)',cap," this is a demonstration sentence. ")
' This is a demonstration Sentence. '
Sorry, that's the best I can do ...
Regex breakdown:
(?:^\s*\w+) #match (optional) whitespace and then 1 word at the beginning of the string
| #regex "or"
(?:[^\s]+\s*$) #match a string of non-whitespace characters followed by (optional) whitespace and the end of the line.
Similar to inspectorG4dget, but using .rsplit()
giving it the maxsplit argument, and .capitalize()
instead.
Note: .split()
also accepts an optional maxsplit argument, to split from the left.
>>> a = " this is a demonstration sentence. "
>>> part_one, part_two = a.rsplit(" ", 1)
>>> " ".join([part_one.capitalize(), part_two.capitalize()])
'This is the demonstration Sentence.'
.rsplit()
splits the text from the right, where the maxsplit argument tells it how many splits to perform. The value 1
will give you one " split " from the right.
>>> a.rsplit(" ", 1)
['this is the demonstration', 'sentence.']
sentence = " this is a demonstration sentence. "
sentence = sentence.split(' ') # Split the string where a space occurs
for word in sentence:
if word: # If the list item is not whitespace
sentence[sentence.index(word)] = word.title()
break # now that the first word's been replaced, we're done
# get the last word by traversing the sentence backwards
for word in sentence[::-1]:
if word:
sentence[sentence.index(word)] = word.title()
break
final_sentence = ' '.join(sentence)
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