11. String Objects¶
11.1 Strings¶
Strings are first-class objects in Python 3.
Some useful string methods:
upper(),swapcase(),format().Strings can be enclosed using
' '" "''' '''
Strings can be assigned as a variable, and format can be used on the variable as well.
s = 'Hello, World {}'s.format(100).
11.2 More string methods¶
Case related:
upper(),lower(),capitalize(),title(),swap(),casefold()Strings are immutable, it can’t be changed. If you change the string using a method, it’s a different object.
Concatenate strings:
s1 + s2.`s3 = ‘this string’ ‘ that string’
For details on string methods, see documentation
11.3 Format¶
Python has rich string-formatting capabilities.
format()method is used to format strings.
x = 42
print('the number is {}'.format(x))
Use formatting instructions are in the documentation
Examples:
{:,}formats a number with appropriate commas{:.3f}fixes three decimal places{:x}for hexadecimal
If Python > 3.6, you can use f-strings. All formatting methods work with f-strings as well.
11.4 Split and join¶
Strings can be split using the
split()method:
s = 'This is a long string with a bunch of words in it.'
print(s.split())
Output:
['This', 'is', 'a', 'long', 'string', 'with', 'a', 'bunch', 'of', 'words', 'in', 'it.']
This can be joined using the
join()method:
s = 'This is a long string with a bunch of words in it.'
l = s.split()
s2 = ' -- '.join(l)
print(s2)
Output:
This -- is -- a -- long -- string -- with -- a -- bunch -- of -- words -- in -- it.