I want to know how to capitalize the first letter of a word in a string

Usually, if you want to convert only the first letter to uppercase, use the following three methods:

mystr = "john, they're bill's friends from the UK"
print mystr.capitalize()

Output: John, they're Bill's friends from the uk

str.capitalize() returns str with only the first letter of str in uppercase and all others in lowercase.

mystr = "john, they're bill's friends from the UK"
print mystr.title()

Output: John, They're Bill's Friends From The Uk

str.title() returns str that converts the first letter of all words into uppercase and other lowercase letters. Since the criteria for dividing words include quotation marks and double quotes as well as blank characters, you should be careful if there are quotes in the string.

import string
mystr = "john, they're bill's friends from the UK"
print string.capwords(mystr)

Output: John. They're Bill's Friends From The Uk

string.capwords(s[, step]) is

It is implemented in that way. If sep is not specified, all blank characters will be changed to one space ("") so please write carefully. If sep is specified, sep is used in split() and join()

import string
mystr = "john.\nthey're bill's        friends from the UK"
print "sep = None:\n", string.capwords(mystr)
print "----------------"
print "sep = '\\n':\n", string.capwords(mystr, "\n")

Result:

sep = None:
John. They're Bill's Friends From The Uk
----------------
sep = '\n':
John.
They're bill's        friends from the uk