Python Programming for Lazy Beginners: A Simple and Easy Tutorial

CHAPTER 8

In this example, the curly braces are empty, and the variables name and age are passed to the format() method as arguments. The format() method will replace the curly braces with the corresponding values.

Formatting  numbers

Numbers are an essential part of programming, and formatting them can help make your output more readable and presentable. In Python, there are several ways to format numbers, each with its own strengths and weaknesses.

One common way to format numbers in Python is to use string formatting with the % operator. For example, you might have a program that calculates the area of a circle and prints it out:

radius = 5
pi = 3.14159
area = pi * radius ** 2
print("The area of the circle is approximately %0.2f square units." % area)

In this example, %0.2f is a placeholder that will be replaced with the value of area when the string is printed. The 0.2 specifies that the number should be rounded to two decimal places.

Another way to format numbers in Python is to use the format() method. This method allows you to specify placeholders in a string using curly braces {} and then fill in those placeholders with formatted numbers using special syntax. For example:

radius = 5
pi = 3.14159
area = pi * radius ** 2
print("The area of the circle is approximately {:.2f} square units.".format(area))

In this example, {:.2f} is a placeholder that will be replaced with the value of area when the string is printed. The .2f specifies that the number should be rounded to two decimal places.

You can also use f-strings to format numbers in Python. F-strings allow you to embed expressions directly in a string using curly braces {} and then format those expressions using special syntax. For example:

radius = 5
pi = 3.14159
area = pi * radius ** 2
print(f"The area of the circle is approximately {area:.2f} square units.")

In this example, {area:.2f} is an expression that will be evaluated and formatted when the string is printed. The .2f specifies that the value of area should be rounded to two decimal places.

So there you have it - several different ways to format numbers in Python! Each method has its own strengths and weaknesses, so choose the one that works best for your specific use case.

Tips and tricks:

Use the end parameter to specify what character(s) to print after each statement. For example, print("Hello",) will print "Hello!" instead of "Hello

".

Use the sep parameter to specify what character(s) to use to separate multiple values passed to the print statement. For example, print("apples", "oranges", "bananas",) will print "apples, oranges, bananas" instead of "apples oranges bananas".

Use the % operator to format strings. For example, print("My name is %s" % "John") will print "My name is John".

Use the format method to format strings. For example, print("My name is {}".format("John")) will print "My name is John".

Use f-strings (formatted string literals) to format strings in a more concise way. For example, name = "John"; print(f"My name is {name}") will print "My name is John".