Get name of variable with highest integer from list Python 3.3.4

Question

(In Python's form of course) However when returning the value I get the value of the variable, not the name of the variable.

My array looks like this:

x = 1

y = 2

z = 3

alloutputs = [x, y, z]

The furthest and most ugliest before needing help is this:

alloutputs[alloutputs.index(max(alloutputs))]

However it's still giving me an integer of the highest value! How would I get back the name of x, y, or z depending on which is largest?

Why would you need the name of the variable, as opposed to the value? There's probably a better option, e.g. turning those variables into dictionary entries. — , Feb 18 '14 at 14:04
Variables are just temporary symbols; they have no meaning outside of the algorithm, and the symbol used for them is arbitrary. — 2rs2ts, Feb 18 '14 at 14:12

Noel Evans · Accepted Answer · 2014-02-18T14:11:51.883

10

As @zhangxaochen says, you need to use a dictionary or named tuple. You could use a dictionary like this:

>>> d = {'x': 1, 'y': 2, 'z': 3}
>>> max(d, key=d.get)
'z'

edited Feb 18 '14 at 14:11

answered Feb 18 '14 at 14:05

Noel Evans

2

You mean `max(d, key=d.get)` – stranac Feb 18 '14 at 14:07
Thanks for the advice on dictionaries, this is still quick for my needs and works great. Thank you. – sunshinekitty Feb 18 '14 at 14:21

zhangxaochen · Answer 2 · 2014-02-18T14:10:26.233

2

A list does not save the names of variables. Use a dictionary or namedtuple:

In [296]: d=dict(x=1, y=2, z=3)

In [297]: from operator import itemgetter
     ...: max(d.items(), key=itemgetter(1))[0]
     ...: 
Out[297]: 'z'

edited Feb 18 '14 at 14:10

answered Feb 18 '14 at 14:04

zhangxaochen

score 2 · Answer 3 · answered Feb 18 '14 at 14:09

2

x, y, z = 1, 2, 3
alloutputs = ["x", "y", "z"]
print max(alloutputs, key = locals().get)

However, if you ever really have to do this, you might want to reconsider your design, IMHO.

answered Feb 18 '14 at 14:09

thefourtheye

2

It turns into perfectly good design when you use a proper, separate dictionary in place of `locals()`. – Feb 18 '14 at 14:13
@delnan You mean, depending on the variable's name is considered a good design? – thefourtheye Feb 18 '14 at 14:15
Not at all. I'm talking about when it *isn't* a variable name, simply a dictionary key (and most likely not hard-coded but coming from a dynamic data source). – Feb 18 '14 at 14:16
@delnan But OP is trying to get the variable's name which has got the maximum value. That is why I want him to reconsider the design. – thefourtheye Feb 18 '14 at 14:17
I concur, I already told OP the same thing in a comment on the question. – Feb 18 '14 at 14:18

score 1 · Answer 4 · answered Feb 18 '14 at 14:15

1

Disclaimer: this is terrible and you should not do this.

[var for var in dir() if eval(var) == max(all)][0]

It does what you want but - as others have said - you would be much better off using a dictionary.

answered Feb 18 '14 at 14:15

Max

score 0 · Answer 5 · answered Feb 18 '14 at 14:08

0

You can use dictionary:

alloutputs = {'x':1,'y':2,'z':3}
maxvalue = max(alloutputs.values())
print [k for k, v in alloutputs.iteritems() if v == maxvalue]

answered Feb 18 '14 at 14:08

Bardia Heydari

3

Looping over a dictionary is like clubbing someone to death with a loaded Uzi. Use the `key` parameter of `max`, e.g. `max(alloutputs, key=alloutputs.get)` or something to that effect. – Feb 18 '14 at 14:10

5 Answers5