Working with strings

Introduction to Python for Developers

George Boorman

Curriculum Manager, DataCamp

Strings are everywhere!

Ball of strings

User profiles

Search engines

Large language models

¹ https://unsplash.com/@steve_j

Python knows single and double quotes

# This works
my_text = 'Hello, my name is George.'

# This also works
my_text = "Hello, my name is George."

' = apostrophe = single quote

Advantages of double quotes

# Single quote string variable containing an apostrophe
my_text = 'Hello, my name's George.'

SyntaxError: invalid syntax.

# Double quote string variable containing an apostrophe
my_text = "Hello, my name's George."
print(my_text)

Hello, my name's George.

Methods

Method = a function that is only available to a specific data type
str methods

# Calling a string method
str_variable.method()

Replacing parts of strings

.replace(text_to_be_replaced, text_to_change_it_to)

my_text = "Hello, my name's George."

# Replace George with John
my_text = my_text.replace("George", "John")

print(my_text)

Hello, my name's John.

Common use cases
- Reformatting e.g., change spaces to underscores
- Fixing or removing typos

Changing case

current_top_album = "For All The Dogs"


# Convert to lowercase
current_top_album = current_top_album.lower()
print(current_top_album)

for all the dogs

# Change to upppercase
current_top_album = current_top_album.upper()
print(current_top_album)

FOR ALL THE DOGS

Sentences and paragraphs

nineteen_eightyfour = "It was a bright cold day in April, and the clocks were striking thirteen."

Multi-line strings

# Create a string variable over multiple lines
harry_potter = """Mr. and Mrs. Dursley, 
of number four Privet Drive, 
were proud to say that they were perfectly normal, 
thank you very much.
"""

"""text""": Multi-line strings
- Enhance readability
- Avoid the need to use special characters
- Longer text such as customer reviews
- Used to describe what functions do

String cheat sheet

Syntax	Purpose	Example
Single quotes `''`	String variable	`my_string = 'My string'`
Double quotes `""`	String variable	`my_string = "My string"`
Triple quotes `""""""`	Multi-line string variable	`my_string = """My string"""`
`str.replace()`	Replacing parts of strings	`my_string = my_string.replace("text_to_remove", "text_to_change_to")`
`str.lower()`	Lowercase string	`my_string = my_string.lower()`
`str.upper()`	Uppercase string	`my_string = my_string.upper()`

¹ https://docs.python.org/3/library/stdtypes.html#string-methods

Let's practice!

Introduction to Python for Developers