title: Basic Data Types in Python 3: Strings

slug: python-basic-data-types-strings

meta: Learn to create and manipulate strings in this series of blog posts on basic data types in Python programming

category: post

date: 2019-10-18

modified: 2019-10-18

newsletter: False

headerimage: /img/191018-python-basic-data-types-strings/header.jpeg

headeralt: Learn basic Python data types in TwilioQuest 3 - Strings

If you're [new to the language](https://wiki.python.org/moin/BeginnersGuide/Overview),

there's a lot to learn on your Python journey. Once you're comfortable writing

and executing code, your first stop becomes learning how to represent data in

your code. No matter the language, there are a few basic data types you'll use

all the time - strings, numbers, booleans, lists, and dictionaries.

Those data types, and how to use them in Python 3, are the topic of this blog

post series. Today, we're starting with __strings__.

If you're learning Python, you might also want to

[check out TwilioQuest 3](https://www.twilio.com/quest/download).

You'll learn about basic data types and much more about Python programming.

Ready to learn how to use strings in Python 3? Let's get started!

One of the most common data types in any programming language is a `string`. A

__string__ represents a series of characters, which you would use to represent

usernames, blog posts, tweets, or any text content in your code. You can create

a string and assign it to a variable like this.

my_name = "Jonathan Joestar"

In Python, strings are considered [immutable](https://www.merriam-webster.com/dictionary/immutable) -

once you create them, they can't be changed. You can, however, use a variety of

methods to create new strings from existing strings. This type of work in

programming is called __string manipulation__. Some web developers joke that at

the end of the day, their job is just mashing strings together - and this isn't

far from the truth!

Here are some common tasks you might undertake when using strings in your code.

Combining strings together - __concatenating__ them - is a very common task. In

Python 3, you can use the `+` operator for this purpose. You can use the `+`

operator multiple times to concatenate multiple strings.

first_name = "Jonathan"

last_name = "Joestar"

full_name = first_name + " " + last_name

Another common task with strings is inserting data into a specific place

within a string. In programming, we call this __string interpolation__. Python 3

provides a handy tool for doing this called ["f" strings](https://www.python.org/dev/peps/pep-0498/).

The "f" in "f strings" stands for __format__ - you can insert other data from

your program into a string when you define it rather than doing complex string

concatenation as demonstrated previously.

Here is an example of creating a formatted string - note the letter `f` is

included just before the first double quote when defining the `message` variable.

When you want to insert data from your program into the string, you can include

it between two "curly braces" - the `{` and `}` characters.

first_name = "Jonathan"

last_name = "Joestar"

age = 24

message = f"My name is {first_name} {last_name}, and I am {age} years old."

print(message)

String objects have a number of [methods](https://docs.python.org/3/library/stdtypes.html#string-methods)

to perform common tasks, like changing the case of strings or trimming their

content. Below, you'll find a few examples. In two of these examples, we are

creating a string variable, and then assigning the same variable a new value,

which is the result of calling a method on a string object.

__Example 1:__ Convert a string to all caps using the `upper` method.

example_string = "am I stoked enough yet?"

example_string = example_string.upper()

print(example_string) # prints "AM I STOKED ENOUGH YET?"

__Example 2:__ Replace all instances of the word `kale` with `tacos`.

example_string = "We're having kale for dinner! Yay kale!"

example_string = example_string.replace("kale", "tacos")

print(example_string) # prints "We're having tacos for dinner! Yay tacos!"

__Example 3:__ Split a comma-delimited string into a list of strings.

example_string = "Apples,Oranges,Pears"

groceries = example_string.split(',')

for item in groceries:

print(item)

[Check our more strings can do](https://docs.python.org/3/library/stdtypes.html#string-methods)

in the Python 3 docs!

Frequently, you will want to convert data from one type into another. In

programming, we call this process __type casting__. There are a number of

__functions__ built in to Python which allow us to do these type conversions

on basic data types.

__Example 1:__ Convert a number into a string using the `str` function.

example_number = 42

converted = str(example_number)

message = "The meaning of life is " + converted

__Example 2:__ Convert a string into a whole number (integer) using `int`.

example_string = "2"

converted = int(example_string)

message = f"Two plus two equals { converted + 2 }"

Strings of text are one of the most common pieces of data you will work with

in programming. Hopefully, you've learned a bit about how to work with strings

in Python 3! Stay tuned for more blog posts in this series to learn more about

basic data types like strings, numbers, booleans, lists, and dictionaries.

Also, be sure to [download and play TwilioQuest 3](https://www.twilio.com/quest/download)

to learn even more about the Python programming language!