control-flow.md

Control Flow

Reference

• https://docs.python.org/3/tutorial/controlflow.html#if-statements
• https://docs.python.org/3/tutorial/controlflow.html#for-statements
• https://docs.python.org/3/tutorial/controlflow.html#break-and-continue-statements-and-else-clauses-on-loops
• https://docs.python.org/3/tutorial/controlflow.html#pass-statements

If Statements

Reference:

• https://docs.python.org/3/tutorial/controlflow.html#if-statements

Use "If" statements to handle conditional logic (i.e. checking whether or not something is true and responding accordingly).

In Python, an "If" statement is defined using the if keyword, followed by a condition to be evaluated, followed by a colon (:), followed by one or more indented lines which contain statement(s) to be executed if the condition is met.

if True:
    print("YES THIS IS TRUE")

#> YES THIS IS TRUE

if 1 == 1:
    print("YES THIS IS TRUE")

#> YES THIS IS TRUE

if False:
    print("YES THIS IS TRUE")

if 1 == 2:
    print("YES THIS IS TRUE")

An "If" statement may include an else keyword, followed by a colon (:), followed by one or more indented lines which contain statement(s) to be executed if the original condition is not met.

if 1 == 2:
    print("YES THIS IS TRUE")
else:
    print("NO THIS IS FALSE")

#> NO THIS IS FALSE

An "If" statement, regardless of whether or not it contains an else keyword, can contain any number of elif keywords, each followed by a colon (:), followed by one or more indented lines which contain statement(s) to be executed if the condition is met. If there is an else keyword, it should come last.

# run this script a few times in a row...
import random

fruit = random.choice(["Apple", "Banana", "Orange"])

if fruit == "Orange":
    print("WE GOT AN ORANGE HERE")
elif fruit == "Banana":
    print("WE GOT A BANANA HERE")
elif fruit == "Peach":
    print("WE GOT A PEACH HERE")
else:
    print("NOT SURE WHAT WE GOT HERE")

As in other languages, statement order matters:

if True:
    print("First")
elif True:
    print("Second")

#> "First"

Case Statements

Python doesn't have "Case" statements. Try to use an "If" statement or a dictionary to accomplish what you are trying to do.