# Functions: they are only run when called and are used to repeat work
# A function can have 0, 1, or as many arguments as you want.
def FUNCTION_NAME(ARGUMENT1, ARGUMENT2, ...):
FUNCTION_BODY # Optional
return FUNCTION_VALUE # Technically optional, but you should always put a return
# Examples of functions
# The identity function
def identity(x):
return x
# A function that sums 0 to x, inclusive
def sumToXInclusive(x):
s = 0
for i in range(x + 1):
s += i
return
# Example of calling a function
sumToXInclusive(5)
15
# Control flow: control flow is used to change the behavior of a program based on a condition
# CONDITION are expressions that result in boolean values
# Exactly 0 or 1 of the bodies will execute
# While elif and else are optional, if you have them, the bodies are not
if CONDITION1:
IF_BODY # NOT optional
# elifs are optional, and you can have as many of them as you want
elif CONDITION2:
ELIF_BODY
# the else is optional and is a catch all. If no other bodies execute, the else body will execute
else:
ELSE_BODY
# Examples of control flow
if True:
print('This will print')
if False:
print('This will NOT print')
else:
print('This will print')
if True:
print('This will print')
elif True:
print('This will NOT print')
# For loops: used for repetitive behavior over an array, string, or range
for VARIABLE in {LIST, STRING, range}:
LOOP_BODY
# Examples of for loops
for i in [4, 6, 1]:
print(i)
for x in 'mango':
print(x)
for x in range(5):
print(x)
# While loops: used for repetitive behavior
# WARNING: they can run forever, be careful of how you use them
while CONDITION:
WHILE_LOOP_BODY
# While loop example
i = 0
while i < 10:
print(i)
i += 1