Python - String

What is a String?

A string is nothing but a sequence of characters. To create a string object in Python, we can enclose a string literal i.e. a string of characters, within delimiters such as -

A pair of single quotes.
A pair of double quotes.
A pair of triple-single quotes.
A pair of triple-double quotes.

Creating string objects

A string object can be constructed by enclosing a string of characters within a pair of single quotes/ double quotes/ triple-single quotes/ triple-double quotes. Let us show you an example with how it is done.

Note : A string literal enclosed within a pair of single or double quotes can only span across a single line, whereas, a string literal enclosed within triple-single or triple-double quotes can span across multiple lines.

An example of creating string objects in different ways.

# Python - Example of string

# A string literal within a pair of single quotes
s1 = 'First'

# A string literal within a pair of double quotes
s2 = "Second"

# A string literal within a pair of triple-single quotes
s3 = '''Third'''

# A string literal within a pair of triple-double quotes
s4 = """Fourth"""


# A string literal within a pair of triple single quotes, spanning across multiple lines
s5 = '''Keep
Smiling!'''
print(s5)

# A string literal within a pair of triple double quotes, spanning across multiple lines
s6 = """Hello
    World!"""
print(s6)

# Printing the values of all string objects, one by one
print(s1)
print(s2)
print(s3)
print(s4)
print(s5)
print(s6)

Output

First
Second
Third
Fourth
Keep 
Smiling
Hello
    World!

Program Analysis

We have created 4 string objects in 4 different ways, where -

The first string object is created by enclosing the string literal First within a pair of single quotes i.e. 'First'
The second string object is created by enclosing the string literal Second within a pair of double quotes i.e. "Second".
The third string object is created by enclosing the string literal Third within a pair of triple-single quotes i.e. '''Third'''.
The fourth string object is created by enclosing the string literal Fourth within a pair of triple-double quotes i.e. """Fourth""".

A string literal should be enclosed within the same type of delimiters.

# Enclosing a string literal within a pair of mismatching delimiters 
s1 = 'Hello"

EOL while scanning string literal

Multi-word strings can also be created in the same way

multi-word string

An example of creating string objects in different ways.

# Python - Example of multi-word string

# A multi-word string literal within a pair of single quotes
s1 = 'Hello World!'

# A multi-word string literal within a pair of double quotes
s2 = "Welcome to DecodeJava!"

# A multi-word string literal within a pair of triple-single quotes
s3 = '''May you all have a wonderful life.'''

# A multi-word string literal within a pair of triple-double quotes
s4 = """Best Wishes!"""


# Printing the values of all string objects, one by one
print(s1)
print(s2)
print(s3)
print(s4)

Output

Hello World!
Welcome to DecodeJava!
May you all have a wonderful life.
Best Wishes!

Program Analysis

The first string object is created by enclosing the string literal Hello World! within a pair of single quotes.
The second string object is created by enclosing the string literal Welcome to DecodeJava! within a pair of double quotes.
The third string object is created by enclosing the string literal May you all have a wonderful life. within a pair of triple single.
The fourth string object is created by enclosing the string literal Best Wishes! within a pair of triple-double quotes.

String objects can be added by using the + operator

# Python - String objects can be added by using the + operator

# Creating the first string object
s1 = 'New '


# Creating the second string object
s2 = 'York'


# Creating the third string object
s3 = 'Delhi'		


# Creating the fourth string object
s4 = 'Castle'


# Creating the fifth string object by concatenating two string literals
s5 = 'Never ' + 'Give ' + 'Up!'


# Addition of two string objects by + operator
print(s1 + s2)
print(s1 + s3)
print(s1 + s4)
print(s5)

Output

NewYork
NewDelhi
NewCastle
Never Give Up!

A string cannot include its own delimiters without preceding it with a backslash.

We cannot create a string object from a string literal which includes its own delimiters unless this delimiter comes right after a backslash \.
We can create a string object from a string literal which includes delimiters other than its own type without needing a backslash.

# Python - Example of string
 
 
# A string literal enclosed within a single quotes and
# It includes single quotes, preceding a backslash.
s1 = 'He\'s a good guy'


# A string literal enclosed within a double quotes and
# It includes double quotes, preceding a backslash.
s2 = "He said - \"I didn't do it\""


# A string literal enclosed within a pair of single quotes can
# include double/triple quotes without needing a backslash
s3 = '"Be yourself, everyone else is already taken - Oscar Widle"'


# A string literal enclosed within a pair of double quotes can
# include single/triple quotes withou needed a backslash
s4 = "It's a beautiful day today!"



# A string literal enclosed within a pair of triple-double quotes can
# include single quotes but a double quote in it must precede a backslash.
s5  = """\"Never say - I can't\""""


# Printing the string objects
print(s1)
print(s2)
print(s3)
print(s4)
print(s5)

Output is :

He's a good guy.
He said - "I didn't do it"
"Be yourself, everyone else is already taken - Oscar Widle"
It's a beautiful day today!
"Never say - I can't

As you can see in the output, a string enclosed within a pair of single quotes can only include single quotes if it is preceded by a backslash \
A string enclosed within a pair of double quotes can only include a double quote, if it is preceded by a backslash \
A string enclosed within a pair of triple-double quotes can only include a double quote, if it precedes a backslash \