Question

Consider this example

def dump(value):
    print value

items = []    
for i in range(0, 2):
    items.append(lambda: dump(i))

for item in items:
    item()

output:

1
1

how can i get:

0
1

Answer 1

You can use a parameter with a default value on the lambda:

for i in range(0, 2):
    items.append(lambda i=i: dump(i))

This works because the default value is evaluated when the function is defined, not when it is called.