his code, [x**2 for x in range(10)] , is an example of a

Example 1: python list comprehension

nums = [4, -7, 9, 1, -1, 8, -6]
half_of_nums = [x/2 for x in nums] #[2, -3.5, 4.5, 0.5, -0.5, 4, -3]

#optionally you can add an if statement like this
half_of_positive_nums = [x/2 for x in nums if x>=0] #[2, 4.5, 0.5, 4]

Example 2: x for x in python

# This could be said as:
x for x in thing: 
# Or
for x in thing:
    return x # Or whatever that puts x in some variable

# Same thing, just really dodgy syntax.