Python Strings – A Detailed Introduction

In Python, strings are one of the most fundamental data types and are used to store sequences of characters. They can be enclosed in either single quotes (') or double quotes ("), and both notations are treated identically.

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

Inserting Quotes Within Strings

You can include quotation marks inside a string by alternating the enclosing quotation style. Here are some examples:

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

Assigning Strings to Variables

Strings can be assigned to variables using the equals sign:

a = "Hello"
print(a)

Multiline Strings

Python allows the creation of multiline strings using triple quotes (either single or double):

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

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

Note: Line breaks are preserved in the output exactly as written in the code.

Strings as Arrays

Strings in Python are arrays of Unicode characters. Python lacks a dedicated character data type, so individual characters are simply strings of length one. You can access elements in a string using square brackets:

a = "Hello, World!"
print(a[1])  # Outputs 'e'

Iterating Through Strings

You can loop through the characters of a string using a for loop:

for x in "banana":
    print(x)

To explore loops in greater detail, refer to the Python For Loops section on Devyra.

Finding String Length

The len() function returns the number of characters in a string:

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

Checking String Content

To verify whether a particular phrase or character exists within a string, use the in keyword:

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

You can also use this within an if statement for conditional logic:

if "free" in txt:
    print("Yes, 'free' is present.")

Negating String Presence

To determine if a character or phrase is absent from a string, use the not in keyword:

print("expensive" not in txt)

Within a condition:

if "expensive" not in txt:
    print("No, 'expensive' is NOT present.")

To deepen your understanding of conditional logic, explore the Python If…Else section on Devyra.