Python, matching two list's elements

x= [0,2,3,5,6];
y= [64,384,1024,4096,384];
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The above are two arrays I'm using. Im trying to match the elements together in a pythonic way

example:

if xType is 2 i want to compute a variable called yType to correspond to its value(position wise) in y. so i should get y = 384. if xType = 3 i should get 1024.

How would i go about doing this

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If your specific aim is to generate a dict from the two lists you've given, use zip:

>>> x = [0,2,3,5,6]
>>> y = [64,384,1024,4096,384]
>>> dict(zip(x, y))
{0: 64, 2: 384, 3: 1024, 5: 4096, 6: 384}

And get rid of those semicolons!

If you don't need a mapping type, but just want to create pairs of items, zip alone will do:

>>> zip(x, y)
[(0, 64), (2, 384), (3, 1024), (5, 4096), (6, 384)]

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This is so short, even Stack Overflow did not allow me to submit such a short answer:

y[x.index(2)]

This will return element from y corresponding to the position of 2 or any other given value from within x list.

Hope it helped :)

Ps. Indeed dictionaries may be something you need. Try using them.

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If the elements in x are unique, you can use them as the keys in a dict to lookup the elements in y that have the same index. Like this:

x = [0,2,3,5,6]
y = [64,384,1024,4096,384]

y_from_x = dict(zip(x,y))

print y_from_x[2] # prints 384
print y_from_x[3] # prints 1024

This is useful if you want to do lots of lookups, but if you want to do just one lookup Tadeck's answer is more efficient

---

a = {0: 64, 2:384, ...}

look up 'maps in python' or something like that

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>>> xymap = dict(zip(x, y))
>>> xymap[2]
384

However, if you also need to lookup elements in x for y, you'll need a yxmap as well. And if you need these to be lists for some reason (perhaps because you're modifying them during the course of your program), you could use i = x.index(2) and then y[i].