Comprehension
- It’s basically ‘one line for loop’ in list, set and dictionary
- [< loop statement > for < loop variable > in < loop range >]
- [< loop statement > for < loop variable > in < loop range > if < conditional statement >]
data = {}
for x in range(10):
data.append(x**2)
# apply the same logic into comprehension
data = { x**2 for x in range(10)}
print(data)
[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]
Examples
data1 = [ v + 2 for v in range(6)]
print(data1)
[2, 3, 4, 5, 6, 7]
data2 = [ v + 2 for v in range(6) if v % 2 == 0]
[2, 4, 6]
combi = []
for x in [1, 2, 3]:
for y in [3, 1, 4]:
if x != y:
combi.append((x, y))
# apply the same logic into comprehension
combi = [ (x, y) for x in [1, 2, 3] for y in [3, 1, 4] if x != y ]
print(combi)
[(1, 3), (1, 4), (2, 3), (2, 1), (2, 4), (3, 1), (3, 4)]
Let’s see how it works on dict type!
{ x : y for x, y in [(1, 'one'), (2, 'two')] }
{1: 'one', 2: 'two'}
{ x : x + 1 for x in range(1, 4) }
{1: 2, 2: 3, 3: 4}
