In Python, a variable is a way to store and access a value in the memory of a computer. A variable is assigned a value using the assignment operator (=), and the value of the variable can be accessed by referencing its name.
For example:
x = 5
print(x)
This code will output 5, because the variable x is assigned the value of 5.
You can also use variables to perform calculations or operations. For example:
x = 5
y = 3
z = x + y
print(z)
This code will output 8, because the variable z is assigned the value of x + y, which is 5 + 3.
You can also use variables to store different types of data, such as strings and lists. For example:
name = "John Doe"
numbers = [1, 2, 3, 4, 5]
The variable name is a string, and the variable numbers is a list.
In python we have different inbuilt functions to perform operation on variables like
len() #finds the length of the variable
type() #finds the datatype of the variable
x = "Hello World"
print(len(x)) #will give length of x which is 11
print(type(x)) #will give datatype of x which is string
You can also use variables as arguments in functions. For example:
def multiply(x, y):
return x * y
result = multiply(5, 3)
print(result)
This code will output 15, because the function multiply() multiplies its two arguments, which are the variables x and y, with the values of 5 and 3 respectively.
Using variables to store user input:
name = input("What is your name? ")
print("Hello, " + name + "!")
In this example, the input() function is used to ask the user for their name, and the value entered is stored in the variable name. The print() function is then used to display a greeting message using the value stored in the variable.
Using variables to store results of calculations:
radius = 5
pi = 3.14
area = pi * (radius ** 2)
print("The area of a circle with radius " + str(radius) + " is " + str(area))
In this example, the variables radius, pi, and area are used to store the radius of a circle, the value of pi, and the area of the circle, respectively. The ** operator is used to raise the value of radius to the power of 2.
Using variables to store lists and accessing individual elements:
colors = ["red", "green", "blue"]
print("The first color in the list is " + colors[0])
In this example, the variable colors is used to store a list of three colors. The square brackets [] are used to access individual elements in a list, and the index of the element to be accessed is placed inside the brackets. In this case, the first element in the list (at index 0) is “red”.
Using variables as function arguments:
def add(a, b):
return a + b
x = 5
y = 3
result = add(x, y)
print("The sum of " + str(x) + " and " + str(y) + " is " + str(result))
In this example, a function named add() is defined which takes two arguments a and b, and returns their sum. The variables x and y are assigned values 5 and 3 respectively. The function is called by passing the variables as arguments and the returned value is stored in variable result.