How can I capitalize the first letter of each word in a string?

Just because this sort of thing is fun for me, here are two more solutions.

Split into words, initial-cap each word from the split groups, and rejoin. This will change the white space separating the words into a single white space, no matter what it was.

s = 'the brown fox'
lst = [word[0].upper() + word[1:] for word in s.split()]
s = " ".join(lst)

EDIT: I don’t remember what I was thinking back when I wrote the above code, but there is no need to build an explicit list; we can use a generator expression to do it in lazy fashion. So here is a better solution:

s = 'the brown fox'
s = ' '.join(word[0].upper() + word[1:] for word in s.split())

Use a regular expression to match the beginning of the string, or white space separating words, plus a single non-whitespace character; use parentheses to mark “match groups”. Write a function that takes a match object, and returns the white space match group unchanged and the non-whitespace character match group in upper case. Then use re.sub() to replace the patterns. This one does not have the punctuation problems of the first solution, nor does it redo the white space like my first solution. This one produces the best result.

import re
s = 'the brown fox'

def repl_func(m):
    """process regular expression match groups for word upper-casing problem"""
    return m.group(1) + m.group(2).upper()

s = re.sub("(^|s)(S)", repl_func, s)


>>> re.sub("(^|s)(S)", repl_func, s)
"They're Bill's Friends From The UK"

I’m glad I researched this answer. I had no idea that re.sub() could take a function! You can do nontrivial processing inside re.sub() to produce the final result!

If str.title() doesn’t work for you, do the capitalization yourself.

1. Split the string into a list of words
2. Capitalize the first letter of each word
3. Join the words into a single string

One-liner:

>>> ' '.join([s[0].upper() + s[1:] for s in "they're bill's friends from the UK".split(' ')])
"They're Bill's Friends From The UK"

Clear example:

input = "they're bill's friends from the UK"
words = input.split(' ')
capitalized_words = []
for word in words:
    title_case_word = word[0].upper() + word[1:]
    capitalized_words.append(title_case_word)
output = ' '.join(capitalized_words)

Copy-paste-ready version of @jibberia anwser:

def capitalize(line):
    return ' '.join(s[:1].upper() + s[1:] for s in line.split(' '))

The .title() method can’t work well,

>>> "they're bill's friends from the UK".title()
"They'Re Bill'S Friends From The Uk"

Try string.capwords() method,

import string
string.capwords("they're bill's friends from the UK")
>>>"They're Bill's Friends From The Uk"

From the Python documentation on capwords:

Split the argument into words using str.split(), capitalize each word using str.capitalize(), and join the capitalized words using str.join(). If the optional second argument sep is absent or None, runs of whitespace characters are replaced by a single space and leading and trailing whitespace are removed, otherwise sep is used to split and join the words.

I really like this answer:

Copy-paste-ready version of @jibberia anwser:

def capitalize(line):
    return ' '.join([s[0].upper() + s[1:] for s in line.split(' ')])

But some of the lines that I was sending split off some blank ” characters that caused errors when trying to do s[1:]. There is probably a better way to do this, but I had to add in a if len(s)>0, as in

return ' '.join([s[0].upper() + s[1:] for s in line.split(' ') if len(s)>0])

To capitalize words…

str = "this is string example....  wow!!!";
print "str.title() : ", str.title();

@Gary02127 comment, the below solution works with title with apostrophe

import re

def titlecase(s):
    return re.sub(r"[A-Za-z]+('[A-Za-z]+)?", lambda mo: mo.group(0)[0].upper() + mo.group(0)[1:].lower(), s)

text = "He's an engineer, isn't he? SnippetBucket.com "
print(titlecase(text))

As Mark pointed out, you should use .title():

"MyAwesomeString".title()

However, if would like to make the first letter uppercase inside a Django template, you could use this:

{{ "MyAwesomeString"|title }}

Or using a variable:

{{ myvar|title }}

Why do you complicate your life with joins and for loops when the solution is simple and safe??

Just do this:

string = "the brown fox"
string[0].upper()+string[1:]

The suggested method str.title() does not work in all cases.
For example:

string = "a b 3c"
string.title()
> "A B 3C"

instead of "A B 3c".

I think, it is better to do something like this:

def capitalize_words(string):
    words = string.split(" ") # just change the split(" ") method
    return ' '.join([word.capitalize() for word in words])

capitalize_words(string)
>'A B 3c'

Here is a summary of different ways to do it, and some pitfalls to watch out for

They will work for all these inputs:

""           => ""       
"a b c"      => "A B C"             
"foO baR"    => "FoO BaR"      
"foo    bar" => "Foo    Bar"   
"foo's bar"  => "Foo's Bar"    
"foo's1bar"  => "Foo's1bar"    
"foo 1bar"   => "Foo 1bar"     

• Splitting the sentence into words and capitalizing the first letter then join it back together:

   # Be careful with multiple spaces, and empty strings
   # for empty words w[0] would cause an index error, 
   # but with w[:1] we get an empty string as desired
   def cap_sentence(s):
     return ' '.join(w[:1].upper() + w[1:] for w in s.split(' '))
  

• Without splitting the string, checking blank spaces to find the start of a word

    def cap_sentence(s):
      return ''.join( (c.upper() if i == 0 or s[i-1] == ' ' else c) for i, c in enumerate(s) )
  

• Or using generators:

    # Iterate through each of the characters in the string 
    # and capitalize the first char and any char after a blank space
    from itertools import chain 
    def cap_sentence(s):
      return ''.join( (c.upper() if prev == ' ' else c) for c, prev in zip(s, chain(' ', s)) )
  

• Using regular expressions, from steveha’s answer:

    # match the beginning of the string or a space, followed by a non-space
    import re
    def cap_sentence(s):
      return re.sub("(^|s)(S)", lambda m: m.group(1) + m.group(2).upper(), s)
  

Now, these are some other answers that were posted, and inputs for which they don’t work as expected if we define a word as being the start of the sentence or anything after a blank space:

• .title()

    return s.title()
  
  # Undesired outputs: 
  "foO baR"    => "Foo Bar"     
  "foo's bar"  => "Foo'S Bar"   
  "foo's1bar"  => "Foo'S1Bar"       
  "foo 1bar"   => "Foo 1Bar"        
  

• .capitalize() or .capwords()

    return ' '.join(w.capitalize() for w in s.split())    
  # or
    import string
    return string.capwords(s)
  
  # Undesired outputs:
  "foO baR"    => "Foo Bar"      
  "foo    bar" => "Foo Bar"      
  

  using ' ' for the split will fix the second output, but not the first

    return ' '.join(w.capitalize() for w in s.split(' '))    
  # or
    import string
    return string.capwords(s, ' ')
  
  # Undesired outputs:
  "foO baR"    => "Foo Bar"      
  

• .upper()

  Be careful with multiple blank spaces, this gets fixed by using ' ' for the split (like shown at the top of the answer)

    return ' '.join(w[0].upper() + w[1:] for w in s.split())
  # Undesired outputs:
  "foo    bar" => "Foo Bar"                 
  

An empty string will raise an error if you access [1:]. Therefore I would use:

def my_uppercase(title):
    if not title:
       return ''
    return title[0].upper() + title[1:]

to uppercase the first letter only.

Don’t overlook the preservation of white space. If you want to process 'fred flinstone' and you get 'Fred Flinstone' instead of 'Fred Flinstone', you’ve corrupted your white space. Some of the above solutions will lose white space. Here’s a solution that’s good for Python 2 and 3 and preserves white space.

def propercase(s):
    return ''.join(map(''.capitalize, re.split(r'(s+)', s)))

If only you want the first letter:

>>> 'hello world'.capitalize()
'Hello world'

But to capitalize each word:

>>> 'hello world'.title()
'Hello World'

In case you want to downsize

# Assuming you are opening a new file
with open(input_file) as file:
    lines = [x for x in reader(file) if x]

# for loop to parse the file by line
for line in lines:
    name = [x.strip().lower() for x in line if x]
    print(name) # Check the result

Although all the answers are already satisfactory, I’ll try to cover the two extra cases along with the all the previous case.

if the spaces are not uniform and you want to maintain the same

string = hello    world i  am    here.

if all the string are not starting from alphabets

string = 1 w 2 r 3g

Here you can use this:

def solve(s):
    a = s.split(' ')
    for i in range(len(a)):
        a[i]= a[i].capitalize()
    return ' '.join(a)

This will give you:

output = Hello    World I  Am    Here
output = 1 W 2 R 3g

A quick function worked for Python 3

Python 3.6.9 (default, Nov  7 2019, 10:44:02) 
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> capitalizeFirtChar = lambda s: s[:1].upper() + s[1:]
>>> print(capitalizeFirtChar('помните своих Предковъ. Сражайся за Правду и Справедливость!'))
Помните своих Предковъ. Сражайся за Правду и Справедливость!
>>> print(capitalizeFirtChar('хай живе вільна Україна! Хай живе Любовь поміж нас.'))
Хай живе вільна Україна! Хай живе Любовь поміж нас.
>>> print(capitalizeFirtChar('faith and Labour make Dreams come true.'))
Faith and Labour make Dreams come true.

Capitalize string with non-uniform spaces

I would like to add to @Amit Gupta’s point of non-uniform spaces:

From the original question, we would like to capitalize every word in the string s = 'the brown fox'. What if the string was s = 'the brown fox' with non-uniform spaces.

def solve(s):
    # If you want to maintain the spaces in the string, s = 'the brown      fox'
    # Use s.split(' ') instead of s.split().
    # s.split() returns ['the', 'brown', 'fox']
    # while s.split(' ') returns ['the', 'brown', '', '', '', '', '', 'fox']
    capitalized_word_list = [word.capitalize() for word in s.split(' ')]
    return ' '.join(capitalized_word_list)

Easiest solution for your question, it worked in my case:

import string
def solve(s):
    return string.capwords(s,' ') 
    
s=input()
res=solve(s)
print(res)

The .title() method won’t work in all test cases, so using .capitalize(), .replace() and .split() together is the best choice to capitalize the first letter of each word.

eg: def caps(y):

     k=y.split()
     for i in k:
        y=y.replace(i,i.capitalize())
     return y

You can try this. simple and neat.

def cap_each(string):
    list_of_words = string.split(" ")

    for word in list_of_words:
        list_of_words[list_of_words.index(word)] = word.capitalize()

    return " ".join(list_of_words)

Another oneline solution could be:

" ".join(map(lambda d: d.capitalize(), word.split(' ')))

You can use title() method to capitalize each word in a string in Python:

string = "this is a test string"
capitalized_string = string.title()
print(capitalized_string)

Output:

This Is A Test String

If you will use the method .title(), then the letters after ‘ will also become uppercase. Like this:

>>> "hello world's".title()
"Hello World'S"

To avoid this, use the capwords function from the string library.
Like this:

>>> import string
>>> string.capwords("hello world's")
"Hello World's"