{"id":17,"date":"2024-01-24T12:46:09","date_gmt":"2024-01-24T12:46:09","guid":{"rendered":"https:\/\/learnpython.elegantwallp.com\/?p=17"},"modified":"2024-01-24T12:46:10","modified_gmt":"2024-01-24T12:46:10","slug":"python-string","status":"publish","type":"post","link":"https:\/\/learnpython.elegantwallp.com\/2024\/01\/24\/python-string\/","title":{"rendered":"Python String"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you\u2019ll learn about Python string and its basic operations.<\/p>\n\n\n\n

Introduction to Python string<\/h2>\n\n\n\n

A string is a series of characters. In Python, anything inside quotes is a string. And you can use either single or double quotes. For example:<\/p>\n\n\n\n

message = 'This is a string in Python' message = \"This is also a string\"<\/code><\/pre>\n\n\n\n
If a string contains a single quote, you should place it in double-quotes like this:<\/p>\n\n\n\n
message = \"It's a string\"<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
And when a string contains double quotes, you can use the single quotes:<\/p>\n\n\n\n
message = '\"Beautiful is better than ugly.\". Said Tim Peters'<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
To escape the quotes, you use the backslash (\\<\/code>). For example:<\/p>\n\n\n\n
message = 'It\\'s also a valid string'<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
The Python interpreter will treat the backslash character (\\) special. If you don\u2019t want it to do so, you can use raw strings by adding the letter\u00a0r<\/code>\u00a0before the first quote. For example:<\/p>\n\n\n\n
message = r'C:\\python\\bin'<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Creating multiline strings<\/h3>\n\n\n\n
To span a string multiple lines, you use triple-quotes \u201c\u201d\u201d\u2026\u201d\u201d\u201d or \u201d\u2019\u2026\u201d\u2019. For example:<\/p>\n\n\n\n
help_message = ''' Usage: mysql command -h hostname -d database name -u username -p password ''' print(help_message)<\/code><\/code><\/pre>\n\n\n\n
It\u2019ll output the following if you execute the program:<\/p>\n\n\n\n
Usage: mysql command -h hostname -d database name -u username -p password<\/code><\/code><\/pre>\n\n\n\n
Using variables in Python strings with the f-strings<\/h2>\n\n\n\n
Sometimes, you want to use the values of\u00a0variables\u00a0in a string.<\/p>\n\n\n\n
For example, you may want to use the value of the\u00a0name<\/code>\u00a0variable inside the\u00a0message<\/code>\u00a0string variable:<\/p>\n\n\n\n
name = 'John' message = 'Hi'<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
To do it, you place the letter\u00a0f<\/code>\u00a0before the opening quotation mark and put the brace around the variable name:<\/p>\n\n\n\n
name = 'John' message = f'Hi {name}' print(message)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Python will replace the\u00a0{name}<\/code>\u00a0by the value of the\u00a0name<\/code>\u00a0variable. The code will show the following on the screen:<\/p>\n\n\n\n
Hi John<\/code><\/code><\/pre>\n\n\n\n
The message<\/code> is a format string, or f-string in short. Python introduced the f-string in version 3.6.<\/p>\n\n\n\n
Concatenating Python strings<\/h2>\n\n\n\n
When you place the string literals next to each other, Python automatically\u00a0concatenates\u00a0them into one string. For example:<\/p>\n\n\n\n
greeting = 'Good ' 'Morning!' print(greeting)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
Good Morning!<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
To\u00a0concatenate two string variables, you use the operator\u00a0+<\/code>:<\/p>\n\n\n\n
greeting = 'Good ' time = 'Afternoon' greeting = greeting + time + '!' print(greeting)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
Good Afternoon!<\/code><\/code><\/pre>\n\n\n\n
Accessing string elements<\/h2>\n\n\n\n
Since a string is a\u00a0sequence\u00a0of characters, you can access its elements using an index. The first character in the string has an index of zero.<\/p>\n\n\n\n
The following example shows how to access elements using an index:<\/p>\n\n\n\n
str = \"Python String\" print(str[0]) # P<\/em> print(str[1]) # y<\/em><\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
How it works:<\/p>\n\n\n\n
    \n
  • First, create a variable that holds a string \"Python String\"<\/code>.<\/li>\n\n\n\n
  • Then, access the first and second characters of the string by using the square brackets []<\/code> and indexes.<\/li>\n<\/ul>\n\n\n\n
    If you use a negative index, Python returns the character starting from the end of the string. For example:<\/p>\n\n\n\n
    str = \"Python String\" print(str[-1]) # g<\/em> print(str[-2]) # n<\/em><\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
    The following illustrates the indexes of the string\u00a0\"Python String\"<\/code>:<\/p>\n\n\n\n
    +---+---+---+---+---+---+---+---+---+---+---+---+---+ | P | y | t | h | o | n | | S | t | r | i | n | g | +---+---+---+---+---+---+---+---+---+---+---+---+---+ 0 1 2 3 4 5 6 7 8 9 10 11 12 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1<\/code><\/code><\/pre>\n\n\n\n
    Getting the length of a string<\/h2>\n\n\n\n
    To get the length of a string, you use the\u00a0len()<\/code>\u00a0function. For example:<\/p>\n\n\n\n
    str = \"Python String\" str_len = len(str) print(str_len)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
    Output:<\/p>\n\n\n\n
    13<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
    Slicing strings<\/h2>\n\n\n\n
    Slicing\u00a0allows you to get a substring from a string. For example:<\/p>\n\n\n\n
    str = \"Python String\" print(str[0:2])<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
    Output:<\/p>\n\n\n\n
    Py<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
    The str[0:2]<\/code> returns a substring that includes the character from the index 0 (included) to 2 (excluded).<\/p>\n\n\n\n
    The syntax for slicing is as follows:<\/p>\n\n\n\n
    string[start:end]<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
    The substring always includes the character at the start<\/code> and excludes the string at the end<\/code>.<\/p>\n\n\n\n
    The start<\/code> and end<\/code> are optional. If you omit the start<\/code>, it defaults to zero. If you omit the end<\/code>, it defaults to the string\u2019s length.<\/p>\n\n\n\n
    Python strings are immutable<\/h2>\n\n\n\n
    Python strings are\u00a0immutable. It means that you cannot change the string. For example, you\u2019ll get an error if you update one or more characters in a string:<\/p>\n\n\n\n
    str = \"Python String\" str[0] = 'J'<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
    Error:<\/p>\n\n\n\n
    Traceback (most recent call last): File \"app.py\", line 2, in <module> str[0] = 'J' TypeError: 'str' object does not support item assignment<\/module><\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
    When want to modify a string, you need to create a new one from the existing string. For example:<\/p>\n\n\n\n
    str = \"Python String\" new_str = 'J' + str[1:] print(new_str)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
    Output:<\/p>\n\n\n\n
    Jython String<\/code><\/code><\/pre>\n\n\n\n
    <\/p>\n","protected":false},"excerpt":{"rendered":"
    Summary: in this tutorial, you\u2019ll learn about Python string and its basic operations. Introduction to Python string A string is a series of characters. In Python, anything inside quotes is a string. And you can use either single or double quotes. For example: If a string contains a single quote, you should place it in […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[15],"tags":[],"class_list":["post-17","post","type-post","status-publish","format-standard","hentry","category-1-fundamentals"],"_links":{"self":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts\/17","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/comments?post=17"}],"version-history":[{"count":1,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts\/17\/revisions"}],"predecessor-version":[{"id":18,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts\/17\/revisions\/18"}],"wp:attachment":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/media?parent=17"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/categories?post=17"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/tags?post=17"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}