Question

Anyone know how to perform following code using list comprehension? I’m stuck due to the if condition, which I don’t know how to apply using list comprehension. Thanks in advance.

x = [{'key':1},{'key':1},{'key':2}, {'key':2}]
y = []

for e in x:
    if e['key'] not in y:
        y.append(e['key'])

>>>print y
[1,2]

Answer 1

For this particular conditional, you can use a set comprehension:

xs = [{'key':1},{'key':1},{'key':2}, {'key':2}]
y = {x['key'] for x in xs}

print y # {1,2}