Can anyone explain please?

Question

Found this question in a challenge but can't understand the for cycle:

What is the output of this code?
a = {0:1, 1:2)
_sum =0
for b in a: _sum += b
print(_sum + b)

Thanks!

Answer 1

Python, I assume?

a for loop looping over a dictionary (a) is actually looping over the keys.

So b will be first 0, then 1.

Also in Python, the loop variable behaves like a regular variable, so it stays at the value it had last - which is 1.

So if you add 0+1+1, the result is 2.

There's a typo: The dictionary should end with }.

You might wand to find a more specific title for the question. And can you maybe add tags to help other users finding it if need be? Could be for example 'Python' and 'challenge'.

Answer 2

Thanks HonFu! And what if I wanted to cycle through the values of the dictionary instead?
Sorry for the format of the question-still trying to figure out how it all works!

Answer 3

You can use:

for b in a.values():
...

Or let's say, you wanted to add the values to _sum, you could use the same loop as before but write:

for b in a:
_sum += a[b]

Answer 4

Which language?