[Python](EN) Python List Comprehensions

Practice Python List Comprehensions

Environment and Prerequisite

results=[]
for i in range(10):
    results.append(i*2)

results=[x*2 for x in range(10)]

List Comprehensions: List comprehensions provide a concise way to create lists. It can make list much simpler.
It can be used when you make new list which is result of each element’s operation or subset elements of some conditions.

list_name = [element_format for clause]

Cover with brackets([ ]), add element format in the front and add for clause in the end.
As like below example, we can also use nested for loop.

results=[]
for i in range(10):
    results.append(i**2)

results=[x**2 for x in range(10)]

results=[]
for x in [1,3,5]:
    for y in [2,4,6]:
        results.append((x,y))

results=[(x,y) for x in [1,3,5] for y in [2,4,6]]

from math import pi

results=[]
for i in range(1, 6):
    results.append(str(round(pi, i)))

from math import pi
results=[str(round(pi, i)) for i in range(1, 6)]

results=[]
for x in [1,2]:
    for y in [3,4]:
        for z in [5,6]:
            results.append((x,y,z))

results=[(x,y,z) for x in [1,2] for y in [3,4] for z in [5,6]]

results=[]
for x in range(20):
    if x%2 == 0:
        results.append(x)

results=[x for x in range(20) if x%2 == 0]