String formatting

There are a couple of ways to format our output, making our output more readable. We would go with the f"... {some_value}" approach known as string interpolation (f-strings).
The {} provides the means to insert values into our string as we write it out. some_value is the value we pass into the string, whereby f means format. The string must begin with the f followed by string delimiters (double or single quote).

Example

# Consider a simple program to take the users
# name and age and then print them to the screen

name = input("Enter name: ")
age = input("Enter age: ")

print(f"User name: {name}\nUser age: {age}")

# Another sample code
# A program to find the area of a triangle
# The area of a triangle is half the product of the base
# (length) and height of the triangle

height = float(input("Enter height of triangle: "))
base = float(input("Enter base of triangle: "))
area = 0.5 * base * height

print(f"The area of a triangle of height, {height}")
print(f" and base, {base} has an area of {area}")

When we have a float, such as, 3.14159 we could round it with the round(number, digit) function to 2-decimal places then print it out.

pi = 3.14159
rounded_pi = round(pi, 2)
print(f"pi, {pi}, rounded to 2d.p is {rounded_pi}")

There is a simple way to do that using f-strings.

pi = 3.14159
print(f"pi, {pi}, rounded to 2d.p is {pi:.2f}")

Practicals

Using the new concept in this exercise and the white space character, newline - \n and one print function. Write a program that takes users full name and their favourite number. Print to the screen the string, <full name> thinks <num / 3> is special.

Given <full name> as, Daniel and <number> as 23, print, Daniel thinks 7.667 is special. Divide the <number> by 3 and round it to 3 decimal places.

Summary

• One may use f"... {}" to format a string
• f - means format
• {} allows us to insert values directly into the string