If conditions

Important for the if conditions and for the for loop is to have a colon after the statement and then have everything in this block indented. So do no introduce additional indentations, this will cause an error.

# Defining an if condition, this could also be used to compare two variables

a = 2
if a > 10 and a <= 50:
    print("a is large")
elif a > 50:
    print("a is very large")
else:
    print("a is small")

Here is a table of boolean operation that Python supports: (All of them support short circuit)

And, Or

a	b	a and b	a or b
False	False	False	False
False	True	False	True
True	False	False	True
True	True	True	True

Any, All

l	any(l)	all(l)
[]	False	False
[False]	False	False
[True]	True	True
[False, True]	True	False
[True, False]	True	False
[True, True]	True	True
[False, False, True]	True	False
[True, True, True]	True	True
[…, True, …]	True	False
[…, False, …]	True	False

For loops and if conditions

Now let’s combine a for loop and if condition to solve the following exercise.

Attention

Exercise 3.1:

• Create a vector including numbers from 1 to 9.

• Using a for loop to iterate over each of these numbers.

• If the number is odd (which you can check using the % (modulus) operator) then add a 1 to the number and print the number.

• If the number is even then simply print this number.