Iterators and Generators Homework - Solution

Problem 1

Create a generator that generates the squares of numbers up to some number N.



In [10]:

    
def gensquares(N):
    for i in range(N):
        yield i ** 2



In [11]:

    
for x in gensquares(10):
    print x

Problem 2

Create a generator that yields "n" random numbers between a low and high number (that are inputs). Note: Use the random library. For example:



In [6]:

    
import random

random.randint(1,10)









    Out[6]:





6



In [7]:

    
def rand_num(low,high,n):
    
    for i in range(n):
        yield random.randint(low, high)



In [9]:

    
for num in rand_num(1,10,12):
    print num

Problem 3

Use the iter() function to convert the string below



In [17]:

    
s = 'hello'

s = iter(s)

print next(s)

Problem 4

Explain a use case for a generator using a yield statement where you would not want to use a normal function with a return statement.

If the output has the potential of taking up a large amount of memory and you only intend to iterate through it, you would want to use a generator. (Multiple answers are acceptable here!)

Extra Credit!

Can you explain what bonus is in the code below? (Note: We never covered this in lecture!)



In [18]:

    
my_list = [1,2,3,4,5]

gencomp = (item for item in my_list if item > 3)

for item in gencomp:
    print item

4
5