Learnpython: Conditions

Python uses boolean logic to evaluate conditions. The boolean values True and False are returned when an expression is compared or evaluated. For example:

x = 2
print(x == 2) # prints out True
print(x == 3) # prints out False
print(x < 3) # prints out True

# Output: 
# True
# False
# True

Notice that variable assignment is done using a single equals operator "=", whereas comparison between two variables is done using the double equals operator "==". The "not equals" operator is marked as "!=".

Boolean operators

The "and" and "or" boolean operators allow building complex boolean expressions, for example:

name = "John"

age = 23

# Checks two condtions: That the string variable name is equal to the string "John" and that the Integer variable age is equal to 23
if name == "John" and age == 23:
    print("Your name is John, and you are also 23 years old.")

if name == "John" or name == "Rick":
    print("Your name is either John or Rick.")

The "in" operator

The "in" operator could be used to check if a specified object exists within an iterable object container, such as a list:

name = "John"
if name in ["John", "Rick"]:
    print("Your name is either John or Rick.")