Strings

Text values are called strings. In Python, strings are defined by single quotes, double quotes, triple-single or triple-double-quotes:

first = 'Emily'
first = "Emily"
first = '''Emily'''
first = """Emily"""

Special characters

Some characters in Python require special attention:

character	meaning
\n	Newline character
\t	tabulator
\\	normal, single backslash

Additionally, Python 3 encodes Unicode characters including German Umlauts, Chinese and Arab alphabets by default. However, they may not be interpreted in the same way in different environments. Just be a bit careful when using them.

String concatenation

The operator + also works for strings, only that it concatenates the strings. It does not matter whether you write the strings as variables or as explicit values.

With first = 'Emily' and last = 'Smith' the following three statements have the same result:

name = first + last
name = first + "Smith"
name = "Emily" + "Smith"

Accessing single characters

Using square brackets, any character of a string can be accessed. This is called indexing. The first character has the index [0], the second [1] and the fourth has the index [3].

name[0]
name[3]

With negative numbers, you can access single characters from the end, the index [-1] being the last, [-2] the second last character and so on:

name[-1]
name[-2]

Note that none of these modify the contents of the string variable.

Creating substrings

Substrings can be formed by applying square brackets with two numbers inside separated by a colon (slices). The second number is not included in the substring itself.

name = 'Emily Smith'
name[0:5]
name[1:4]
name[6:11]
name[:3]
name[-4:]

String methods

Every string in Python brings a list of functions to work with it. As the functions are contained within the string they are also called methods. They are used by adding the . to the string variable followed by the method name.

Below you find a few of the available methods:

Changing case

name = 'Manipulating Strings \n'
name.upper()
name.lower()

Removing whitespace at both ends

name.strip()

Cutting a string into columns

name.split(' ')

Searching for substrings

name.find('ing')

The method returns the start index of the match. The result -1 means that no match has been found.

Replacing substrings

name.replace('Strings','text')

Checking beginning and end of a string

Both of the following functions return a boolean:

name.startswith('Man')
name.endswith('ings')