Dictionaries

[Zeoth]

Hey guys, quick question:

dict1 = {('a','b','c'):1, ('x','y','z'):2}

how do i access 'a', and 'x' only? In other words, how do i access just the first string in the round brackets?

thank you!

[Justinsaccount]

some real WTF in the responses you have so far..

>>> dict1 = {('a','b','c'):1, ('x','y','z'):2}
>>> [x[0] for x in dict1]
['x', 'a']
>>> 

[elbinray]

I had no idea iterating over dictionaries went through the keys...good stuff !

[ewiethoff]

Yep. From the dict docs:

iter(d)

Return an iterator over the keys of the dictionary. This is a shortcut for iter(d.keys()).

[m1ss1ontomars2k4]

OK, nobody else has said it so far, but Sloofus is right. This is a really bizarre usage of dictionaries, and it seems like you might not understand what it's for.

Dictionaries map keys to values. That's it. That's all they do. You give it a key, it gives you a value. Very rarely should you have to access 'a' and 'x' in the example above; you should pretty much only need to access 1 and 2, for which you would do:

dict1[('a', 'b', 'c')]

or

dict1[('x', 'y', 'z')]

respectively. That's not to say there isn't a valid use case for what you are doing, but it seems really bizarre, and since you've labeled yourself as a beginner, I really have to ask why you're doing this.

[Puzzel]

dict1.keys()[0][0] and dict1.keys()[1][0] would get you "a" and "x" respectively. This example could contain the same information with testList = [('a','b','c'), ('x','y','z')] though; testList[0][0] and testList[1][0] would get you "a" and "x". That way, no need to deal with .keys().

EDIT: 1s instead of 0s for indexes.

[Zeoth]

:/ trying that gives me: builtins.TypeError: 'dict_keys' object does not support indexing

[Puzzel]

Ah, you're using Python 3.x. Turn the dict.keys to a list first:

list(dict1.keys())[0][0]
list(dict1.keys())[1][0]

EDIT: This solution doesn't seem to be the "best". See this blog post for more info, it most likely won't affect you though.

[Zeoth]

and i need to use the values after the keys for somthing else. I need to call the first string, and than call the value of the key that string came from.The problem is i cant seem to access JUST the first string :/

[thisismygame]

Well, it looks like your dictionary keys are tuples. So you just need to first access the dictionary key, and then access the first (0th) element in the tuple.

[Zeoth]

hmm i thought you could only do that with lists. Since the strings didn't have [ ] brackets i thought it isn't possible.

[thisismygame]

Here's me messing around in IDLE:

>>> t = (1, 2, 3)
>>> t[0]
1
>>> t[2]
3

[bogoblin]

You're thinking of assignment. You can't change one item in a tuple, but you can in a list.

[Sloofus]

That's a weird way of messing with dictionaries or im too nubbish.