String Data Type in Python
A String is a sequence of characters. In Python string literals are enclosed in either single quotes or double quotes. 'Hello World' and "Hello World" are same.
Creating a String Variable
To create a string variable in Python, simply a variable name is declared followed by an equal sign = and then the string value enclosed in either single quotes or double quotes.
Example:
x = 'Hello World'
y = "Hello World"
print(x)
print(y)
Output:
Hello World
Assigning a Multiline String
To assign a multiline string to a variable in Python, the string literals are enclosed in triple single or double quotes.
Example:
a = """To assign a multiline string
to a variable in Python, the
string literals are enclosed
in triple quotes."""
b = '''To assign a multiline string
to a variable in Python, the
string literals are enclosed
in triple quotes.'''
print(a)
print(b)
Output:
to a variable in Python, the
string literals are enclosed
To assign a multiline string
to a variable in Python, the
string literals are enclosed
Find String Length
The len() function return the length of a string.
Example:
a = "Hello World"
print(len(a))
Output:
Accessing Single Character of a String
There is no Character data type in Python. A single character having length of 1 is also a string in Python.
In python, a string is an array of Unicode characters. A single character of a string can be accessed using square brackets. The first character always starts from 0 position.
Example:
a = "Hello World"
print(a[1])
Output:
String Slicing
Slicing in Python means getting a range of characters from a string. To return a range of characters, specify the start index and the end index separated by a colon with the square brackets.
Syntax:
string[start index : end index]
Example:
a = "Hello World"
print(a[6:11])
Output:
You can also get the range of characters beginning from the end to the start of the string by using negative index.
Syntax:
string[-start index: -end index]
Example:
a = "4444 2222 5555 9999"
print(a[-19:-4])
Output:
String in
The in keyword is used to check if a certain character is present in a string.
Example:
A = "This is a great world"
b = "great" in A
print(b)
Output:
String not in
The not in keyword is used to check if a certain character is not present in a string.
Example:
A = "This is a great world"
b = "great" not in A
print(b)
Output:
String Format
The format() method is used to format a specified value in a string. It takes arguments, formats them and inserts them in places where curly braces are in a string.
Example:
order_string = "The cost price of this pen is {} and the selling price is {}"
formatted_string = order_string.format(10,15)
print(formatted_string)
Output:
String Concatenation
String concatenation is the joining of two or more strings together. To concatenate two or more string use the + operator.
Example:
string_1 = "Hello"
string_2 = "How are you?"
string_3 = "Have a great day!"
string_4 = "Where do you live?"
message = string_1 + " " + string_2 + " " + string_3 + " " + string_4;
print(message)
Output:
Convert String to Lowercase
The lower() function is used to convert string to lowercase.
Example:
a = "HELLO WORLD"
result = a.lower()
print(result)
Output:
Convert String to Uppercase
The upper() function is used to convert string to uppercase.
Example:
a = "hello world"
result = a.upper()
print(result)
Output:
String Methods
String has a set of useful built-in methods. Some of the methods are:
String Methods | Description | Example |
capitalize() | Converts the first letter of a string to capital. |
x = "hello world"
y = x.capitalize() |
count() | Count and return the number of times a specified character occcurs in a string. |
a = "This is a great"
b = a.count("is") |
decode() | Decodes a value to string. |
x = "hello world"
y = x.decode("rld") |
encode() | Encodes a string. |
x = "hello world"
y = x.encode("rld") |
endswith() | Returns true if a string ends with a specified value. |
x = "hello world"
y = x.endswith("rld") |
find() | Searches the string for a specified character and returns its position. |
a = "This is a great"
b = a.find("is") |
lower() | Returns the string in lowercase. |
x = "Hello World"
y = x.lower() |
replace() | Replaces old string with new string. |
x = "Hello World"
y = x.replace("H", "h") |
rstrip() | Removes any trailing whitespace and returns a new string. |
x = "Hello World "
y = x.strip() |
strip() | Removes any leading and trailing whitespace and returns a new string. |
x = " Hello World "
y = x.strip() |
split() | Splits a string if the specified splitting character is found and returns an array. |
x = "Hello, World"
y = x.split(",") |
swapcase() | Converts uppercase to lowercase and lowercase to uppercase. |
x = "Hello World"
y = x.swapcase() |
startswith() | Returns true if a string starts with a specified value. |
x = "hello world"
y = x.startswith("he") |
title() | Changes the first character of every word to uppercase. |
x = "hello world"
y = x.title() |
upper() | Returns the string in uppercase. |
x = "Hello World"
y = x.upper() |