Creating a String in Python

Here’s how a string in Python can be created:

message1 = "I am a string"
message2 = 'I am also a string'

Other data types such as integers, float, and booleans can also be strings if they are wrapped in quotes:

Strings are immutable, meaning they cannot change. Every time an operation is performed on a string, a new string is created in memory.

Accessing the Characters of a String in Python

A string in Python is a sequence of characters. Like lists, strings support indexing and slicing. This means each character in a string can be individually accessed by index, like with the elements in a list:

myString = "Hello, World!"
var_1 = myString[0]
var_2 = myString[7:]
var_3 = myString[1:4]
print("var_1: " + var_1) 
print("var_2: " + var_2) 
print("var_3: " + var_3) 

If an attempt is made to access an index out of bounds, it will return an IndexError:

Multi-line Strings in Python

A string in Python can be long or short. For longer text, a multi-line string can be used. Multi-line strings begin and end with three single or double quotes:

my_string = """This is a
multi-line
string."""

Escape Characters in a String in Python

Sometimes, a string in Python may have a character that Python tries to interpret, such as ':

my_string = 'It's a lovely day!'
print(my_string)

This will raise an error, because the interpreter thinks the second ' marks the end of the string:

  File "main.py", line 1
    my_string = 'It's a lovely day!'
                    ^
SyntaxError: invalid syntax

These characters can be “escaped” by adding a backslash beforehand. The \ is called an escape character.

The backslash will not be visible if the string is printed:

my_string = 'It\'s a lovely day!'
print(my_string) 

This problem can be avoided by wrapping strings containing ' characters in double quotes:

my_string = "It's a lovely day!"
print(my_string) 

Python also has a series of non-printing characters that can modify strings. For example, \n adds a new line and \t adds a tab:

note = "I am on top!\nI am on bottom. \n\tI am indented!"
print(note)

This will output:

I am on top!
I am on bottom.
  I am indented!

Modifying a String in Python

Python has special operators to modify strings. For example, + can be used to concatenate strings and * can be used to multiply a string. The keyword in can be used to see if a given character or substring exists in a string:

string_one = "Hello, "
string_two = "World! "
combo = string_one + string_two
print(combo) 
new_combo = combo * 2
print(new_combo) 
if "World" in new_combo:
  print("It's here!") 

Strings can also be formatted with either of the following:

• The f/F flag (placed before the opening quotation mark).
• The .format() method (requires manually adding placeholders).

Comparing Strings in Python

Python can use comparison operators to compare the contents of two strings. The operators behave as they do with numeric arguments:

This codebyte example demonstrates string comparison in Python:

Frequently Asked Questions

1. How to concatenate two strings in Python?

You can use the + operator or .join() method to concatenate strings in Python:

"Hello" + " " + "World"  
" ".join(["Hello", "World"])  

2. How can I slice a string in Python?

String slicing in Python uses the format string[start:stop:step]:

text = "HelloWorld"
print(text[1:5])  

3. What are the 4 string functions in Python?

Here are some common Python string methods:

• .lower(): Converts to lowercase
• .upper(): Converts to uppercase
• .strip(): Removes whitespace
• .replace(): Replaces substrings
• .split(): Splits the string into a list
• .find(): Finds the index of a substring