Strings
Strings in python are surrounded by either single quotation marks, or double quotation marks.
'hello' is the same as "hello".
You can display a string literal with the print[]
function:
Assign String to a Variable
Assigning a string to a variable is done with the variable name followed by an equal sign and the string:
Multiline Strings
You can assign a multiline string to a variable by using three quotes:
Example
You can use three double quotes:
a = """Lorem ipsum dolor sit amet,
consectetur adipiscing elit,
sed do eiusmod tempor incididunt
ut labore et dolore magna aliqua."""
print[a]
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Or three single quotes:
Example
a = '''Lorem ipsum dolor sit amet,
consectetur
adipiscing elit,
sed do eiusmod tempor incididunt
ut labore et dolore magna aliqua.'''
print[a]
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Note: in the result, the line breaks are inserted at the same position as in the code.
Strings are Arrays
Like many other popular programming languages, strings in Python are arrays of bytes representing unicode characters.
However, Python does not have a character data type, a single character is simply a string with a length of 1.
Square brackets can be used to access elements of the string.
Example
Get the character at position 1 [remember that the first character has the position 0]:
a = "Hello, World!"
print[a[1]]
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Looping Through a String
Since strings are arrays, we can loop through the characters in a string, with a for
loop.
Example
Loop through the letters in the word "banana":
for x in "banana":
print[x]
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Learn more about For Loops in our Python For Loops chapter.
String Length
To get the length of a string, use the len[]
function.
Example
The len[]
function returns the length of a string:
a = "Hello, World!"
print[len[a]]
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Check String
To check if a certain phrase or character is present in a string, we can use the keyword
in
.
Example
Check if "free" is present in the following text:
txt = "The best things in life are free!"
print["free" in txt]
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Use it in an if
statement:
Example
Print only if "free" is present:
txt = "The best things in life are free!"
if "free" in txt:
print["Yes,
'free' is present."]
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Learn more about If statements in our Python If...Else chapter.
Check if NOT
To check if a certain phrase or character is NOT present in a string, we can use the keyword not in
.
Example
Check if "expensive" is NOT present in the following text:
txt = "The best things in life are free!"
print["expensive" not in txt]
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Use it in an if
statement:
Example
print only if "expensive" is NOT present:
txt = "The best things in life are free!"
if "expensive" not in txt:
print["No, 'expensive' is NOT present."]
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Python has a set of built-in methods that you can use on strings.
Note: All string methods returns new values. They do not change the original string.
capitalize[] | Converts the first character to upper case |
casefold[] | Converts string into lower case |
center[] | Returns a centered string |
count[] | Returns the number of times a specified value occurs in a string |
encode[] | Returns an encoded version of the string |
endswith[] | Returns true if the string ends with the specified value |
expandtabs[] | Sets the tab size of the string |
find[] | Searches the string for a specified value and returns the position of where it was found |
format[] | Formats specified values in a string |
format_map[] | Formats specified values in a string |
index[] | Searches the string for a specified value and returns the position of where it was found |
isalnum[] | Returns True if all characters in the string are alphanumeric |
isalpha[] | Returns True if all characters in the string are in the alphabet |
isascii[] | Returns True if all characters in the string are ascii characters |
isdecimal[] | Returns True if all characters in the string are decimals |
isdigit[] | Returns True if all characters in the string are digits |
isidentifier[] | Returns True if the string is an identifier |
islower[] | Returns True if all characters in the string are lower case |
isnumeric[] | Returns True if all characters in the string are numeric |
isprintable[] | Returns True if all characters in the string are printable |
isspace[] | Returns True if all characters in the string are whitespaces |
istitle[] | Returns True if the string follows the rules of a title |
isupper[] | Returns True if all characters in the string are upper case |
join[] | Converts the elements of an iterable into a string |
ljust[] | Returns a left justified version of the string |
lower[] | Converts a string into lower case |
lstrip[] | Returns a left trim version of the string |
maketrans[] | Returns a translation table to be used in translations |
partition[] | Returns a tuple where the string is parted into three parts |
replace[] | Returns a string where a specified value is replaced with a specified value |
rfind[] | Searches the string for a specified value and returns the last position of where it was found |
rindex[] | Searches the string for a specified value and returns the last position of where it was found |
rjust[] | Returns a right justified version of the string |
rpartition[] | Returns a tuple where the string is parted into three parts |
rsplit[] | Splits the string at the specified separator, and returns a list |
rstrip[] | Returns a right trim version of the string |
split[] | Splits the string at the specified separator, and returns a list |
splitlines[] | Splits the string at line breaks and returns a list |
startswith[] | Returns true if the string starts with the specified value |
strip[] | Returns a trimmed version of the string |
swapcase[] | Swaps cases, lower case becomes upper case and vice versa |
title[] | Converts the first character of each word to upper case |
translate[] | Returns a translated string |
upper[] | Converts a string into upper case |
zfill[] | Fills the string with a specified number of 0 values at the beginning |
Note: All string methods returns new values. They do not change the original string.
Learn more about strings in our Python Strings Tutorial.