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:

print("Hello")
print('Hello')

You can use quotes inside a string, as long as they don't match the quotes surrounding the string:

print("It's alright")
print("He is called 'Johnny'")
print('He is called "Johnny"')

Assigning a string to a variable is done with the variable name followed by an equal sign and the string:

a = "Hello"
print(a)

You can assign a multiline string to a variable by using three quotes:

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)

Or three single quotes:

a = '''Lorem ipsum dolor sit amet,
consectetur adipiscing elit,
sed do eiusmod tempor incididunt
ut labore et dolore magna aliqua.'''
print(a)

Note: In the result, the line breaks are inserted at the same position as in the code.

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:

a = "Hello, World!"
print(a[1])

Since strings are arrays, we can loop through the characters in a string with a for loop:

for x in "banana":
  print(x)

To get the length of a string, use the len() function:

a = "Hello, World!"
print(len(a))

To check if a certain phrase or character is present in a string, we can use the keyword in.

Check if "free" is present in the following text:

txt = "The best things in life are free!"
print("free" in txt)

Use it in an if statement:

txt = "The best things in life are free!"
if "free" in txt:
  print("Yes, 'free' is present.")

To check if a certain phrase or character is NOT present in a string, we can use the keyword not in.

Check if "expensive" is NOT present in the following text:

txt = "The best things in life are free!"
print("expensive" not in txt)

Use it in an if statement:

txt = "The best things in life are free!"
if "expensive" not in txt:
  print("No, 'expensive' is NOT present.")

You can return a range of characters by using the slice syntax. Specify the start index and the end index, separated by a colon, to return a part of the string.

Get the characters from position 2 to position 5 (not included):

b = "Hello, World!"
print(b[2:5])

Note: The first character has index 0.

By leaving out the start index, the range will start at the first character:

b = "Hello, World!"
print(b[:5])

By leaving out the end index, the range will go to the end:

b = "Hello, World!"
print(b[2:])

Use negative indexes to start the slice from the end of the string:

Get the characters:

From: "o" in "World!" (position -5)

To, but not included: "d" in "World!" (position -2):

b = "Hello, World!"
print(b[-5:-2])

Python has a set of built-in methods that you can use on strings.

The upper() method returns the string in upper case:

a = "Hello, World!"
print(a.upper())

The lower() method returns the string in lower case:

a = "Hello, World!"
print(a.lower())

Whitespace is the space before and/or after the actual text, and very often you want to remove this space.

The strip() method removes any whitespace from the beginning or the end:

a = " Hello, World! "
print(a.strip())  # returns "Hello, World!"

The replace() method replaces a string with another string:

a = "Hello, World!"
print(a.replace("H", "J"))

The split() method returns a list where the text between the specified separator becomes the list items.

The split() method splits the string into substrings if it finds instances of the separator:

a = "Hello, World!"
print(a.split(","))  # returns ['Hello', ' World!']

To concatenate, or combine, two strings, you can use the + operator.

Merge variable a with variable b into variable c:

a = "Hello"
b = "World"
c = a + b
print(c)

To add a space between them, add a " ":

a = "Hello"
b = "World"
c = a + " " + b
print(c)

As we learned in the Python Variables chapter, we cannot combine strings and numbers like this:

age = 36
txt = "My name is John, I am " + age
print(txt)

But we can combine strings and numbers by using f-strings or the format() method!

F-String was introduced in Python 3.6 and is now the preferred way of formatting strings.

To specify a string as an f-string, simply put an f in front of the string literal, and add curly brackets {} as placeholders for variables and other operations.

Create an f-string:

age = 36
txt = f"My name is John, I am {age}"
print(txt)

A placeholder can contain variables, operations, functions, and modifiers to format the value.

Add a placeholder for the price variable:

price = 59
txt = f"The price is {price} dollars"
print(txt)

A placeholder can include a modifier to format the value.

A modifier is included by adding a colon : followed by a legal formatting type, like .2f which means fixed-point number with 2 decimals:

Display the price with 2 decimals:

price = 59
txt = f"The price is {price:.2f} dollars"
print(txt)

A placeholder can contain Python code, like math operations:

Perform a math operation in the placeholder, and return the result:

txt = f"The price is {20 * 59} dollars"
print(txt)

To insert characters that are illegal in a string, use an escape character.

An escape character is a backslash \ followed by the character you want to insert.

An example of an illegal character is a double quote inside a string that is surrounded by double quotes:

You will get an error if you use double quotes inside a string that is surrounded by double quotes:

txt = "We are the so-called "Vikings" from the north."

To fix this problem, use the escape character \":

The escape character allows you to use double quotes when you normally would not be allowed:

txt = "We are the so-called \"Vikings\" from the north."

Other escape characters used in Python:

Python has a set of built-in methods that you can use on strings. All string methods return new values. They do not change the original string.