Find maximum value in dictionary of lists

Question

How do I find the maximum value of the lists in a dictionary of lists without using a loop? My dictionary looks like:

data = {'key1': list1, 'key2': list2, ... 'keyn': listn}

if I use:

m = max(data.iterkeys(), key=lambda k: data[k])

the output is:

m = 'keyn'

which I don't want to have.

score 3 · Accepted Answer · answered Jul 13 '16 at 08:16

3

Iterate through the items in each list in a generator expression:

m = max(i for v in data.values() for i in v)

answered Jul 13 '16 at 08:16

Moses Koledoye

Thank you! I knew that there was I way like this but (I'm new to python) I didn't get it – themacco Jul 13 '16 at 08:18
@themacco You could catch up with a little reading [Generator Expressions vs. List Comprehension](http://stackoverflow.com/questions/47789/generator-expressions-vs-list-comprehension) – Moses Koledoye Jul 13 '16 at 08:32

Eduard · Answer 2 · 2016-07-13T08:27:31.547

3

myDict = {'key1': [1,2,3], 'key2': [4,5,6]}
maxValue = max((max(myDict[key]) for key in myDict))

output: 6

if your new to python, here is a much readable way of how Moses Koledoye did it:

for v in myDict.values():
    for i in v:
        m = i if i > m else m

edited Jul 13 '16 at 08:27

answered Jul 13 '16 at 08:18

Eduard

Rahul K P · Answer 3 · 2016-07-13T09:47:28.620

0

You can find the maximum value like this. With out using any loop.

max(max(data.values()))

But this answer is valid when the all values are iterable.

In [1]: myDict = {'key1': [1,2,3], 'key2': [4,5,6]}
In [2]: max(max(myDict.values()))
Out[1]: 6

edited Jul 13 '16 at 09:47

answered Jul 13 '16 at 09:42

Rahul K P

3 Answers3