Lesson 5 👉 Functions

Do Now (copy into IDE)

import random
random.randint(0, 3)
random.randint(0, 3)
print random.randint(0, 3)
print random.randint(0, 3)
print random.randint(0, 3)
# In comments:
# What does randint do?
# What do the values 0 and 3 do?
# Try changing those numbers, rerun the program, and write down what changed.
# What is the difference between random.randint(0,3) and print(random.randint(0,3))?

print is a built-in function– it takes an input and produces some output when you use it.

Functions

Why use functions?
→ Reusable Code
If you find yourself doing something more than once, make it a function.

In other words…

**Be lazy. **
**Don’t repeat yourself. **
Make the computer do the work.

Functions have to be defined and then called:

def name_of_function(this):
  """What it do???"""
  print "It prints " + this + "!"

Take a look at this one…

def power(base, exponent):  
    result = base**exponent
    print "%d to the power of %d is %d." % (base, exponent, result)

power(37, 4)  

Write a for loop to print only the odd numbers from this list

list = [3,4,7,13,54,32,653,256,1,41,65,83,92,31]`

Now, iterate and turn your loop into a function called find_odds that takes an input and prints the odd numbers in ANY list.

def find_odds(input):`

To exceed standards, create functions to ADD all of the odd numbers in a list. Then create a function to add all of the even numbers in a list. Test your functions using a randomly generated list of numbers.

def odd_sum(input):
def even_sum(input):

Make a random list

import random
my_randoms = random.sample(range(100), 15)

Checklist

Meeting Standards (3)

for loop prints odd numbers from list
function find_odds takes a list, prints odds.
```
def find_odds(input):
```

Exceeding Standards (4)

function odd_sum adds up all odd numbers
function even_sum adds up all even numbers