We'll start by talking about variables. In programming, a variable is a named location used to store data
in memory. It is called a variable because its value can vary throughout the execution of a program.
Variables must be given unique names, called identifiers. In Python, variable names are case sensitive
and cannot start with a number. They can contain letters, numbers, and underscores.
For example, let's say we want to store the number of apples I have in a variable named apples. We can
do this with the following code:
apples = 5
Now, apples is a variable that stores the value 5. We can use this variable in calculations, such as adding
more apples:
apples = apples + 3
print(apples)
This will output 8, because we added 3 to the value stored in the apples variable.
Next, let's talk about data types. A data type is an attribute that tells what kind of data a particular
variable can hold. There are several basic data types in Python, including int, float, str, and bool.
int is short for integer, which is a whole number, positive or negative, without decimals. For example:
num_apples = 10
num_oranges = -5
float is short for floating point number, which is a number with decimals. For example:
price_per_apple = 0.5
price_per_orange = 0.35
str is short for string, which is a sequence of characters surrounded by quotes. Strings can be enclosed in
either single quotes or double quotes. For example:
name = "Alice"
greeting = 'Hello, world!'
bool is short for boolean, which is a logical value that can be either True or False. For example:
is_hungry = True
is_tired = False
We can also use data types to perform type conversions, such as converting a string to an integer:
age_str = "25"
age_int = int(age_str)
print(type(age_int))
in memory. It is called a variable because its value can vary throughout the execution of a program.
Variables must be given unique names, called identifiers. In Python, variable names are case sensitive
and cannot start with a number. They can contain letters, numbers, and underscores.
For example, let's say we want to store the number of apples I have in a variable named apples. We can
do this with the following code:
apples = 5
Now, apples is a variable that stores the value 5. We can use this variable in calculations, such as adding
more apples:
apples = apples + 3
print(apples)
This will output 8, because we added 3 to the value stored in the apples variable.
Next, let's talk about data types. A data type is an attribute that tells what kind of data a particular
variable can hold. There are several basic data types in Python, including int, float, str, and bool.
int is short for integer, which is a whole number, positive or negative, without decimals. For example:
num_apples = 10
num_oranges = -5
float is short for floating point number, which is a number with decimals. For example:
price_per_apple = 0.5
price_per_orange = 0.35
str is short for string, which is a sequence of characters surrounded by quotes. Strings can be enclosed in
either single quotes or double quotes. For example:
name = "Alice"
greeting = 'Hello, world!'
bool is short for boolean, which is a logical value that can be either True or False. For example:
is_hungry = True
is_tired = False
We can also use data types to perform type conversions, such as converting a string to an integer:
age_str = "25"
age_int = int(age_str)
print(type(age_int))
