Flow control

1. loops
2. conditionals

Loops

Two types of lopls: for, while

for

counter = 0
simple_list = [0,1,2,3,4,5,6,2143,123,7834]
for i in simple_list:
    print(i) # print all values in array
    counter = counter + 1
print('The loop cycled',counter,'times')

0
1
2
3
4
5
6
2143
123
7834
The loop cycled 10 times

# Nested for loops
for i in simple_list[1:4]:
    for j in simple_list[4:7]:
        print(i*j)
    print('outside of j loop',"inside i",i)
print('outside of both loops')

4
5
6
outside of j loop inside i 1
8
10
12
outside of j loop inside i 2
12
15
18
outside of j loop inside i 3
outside of both loops

range

less memory intensive way of storing a list.

First number is inclusive and second number is exclusive of.

print (range(6))

range(0, 6)

for i in range(6): #requires a colon at the end
    print(i)

0
1
2
3
4
5

# specify the starting point of a range.
for i in range(4,10):
        print(i)

4
5
6
7
8
9

# increment by a specific amount
for i in range(2,10,2): # Third numer is the amout to increment by
    print(i)

2
4
6
8

#convert a range to a list trhough
list(range(6,15,3))

[6, 9, 12]

while

At each cycle it checks a condition

i=4
while i < 10: # requires a colon at the end
    print(i)
    i = i+1
print('ouside of loop')

4
5
6
7
8
9
ouside of loop

Conditionals

1. if statement
2. else statement
3. elif statement

i = 3
if i<10:
    print(i,'is less than 10')
else:
    print(i,'is greater than or equal to 10')

3 is less than 10

i = 8
if i > 10:
    print(i,'is greater than 10')
elif i < 3:
    print(i,'is less than 3')
else:
    print(i,'is between 3 and 10')

8 is between 3 and 10

i=3
if i<10:
    print(i,'is less than 10')
elif i<=3:
    print(i, 'is less than or equal to 3')
elif i>4:
    print(i)
else:
    print(i,'is between 3 and 10')
    

3 is less than 10