Let's say I have a dictionary:
data = {'a':1, 'b':2, 'c': 3, 'd': 3}
I want to get the maximum value(s) in the dictionary. So far, I have been just doing:
max(zip(data.values(), data.keys()))[1]
but I'm aware that I could be missing another max value. What would be the most efficient way to approach this?
Based on your example, it seems like you're looking for the key(s) which map to the maximum value. You could use a list comprehension:
[k for k, v in data.items() if v == max(data.values())]
# ['c', 'd']
If you have a large dictionary, break this into two lines to avoid calculating max for as many items as you have:
mx = max(data.values())
[k for k, v in data.items() if v == mx]
In Python 2.x you will need .iteritems().
You could try collecting reverse value -> key pairs in a defaultdict, then output the values with the highest key:
from collections import defaultdict
def get_max_value(data):
d = defaultdict(list)
for key, value in data.items():
d[value].append(key)
return max(d.items())[1]
Which Outputs:
>>> get_max_value({'a':1, 'b':2, 'c': 3, 'd': 3})
['c', 'd']
>>> get_max_value({'a': 10, 'b': 10, 'c': 4, 'd': 5})
['a', 'b']
First of all, find what is the max value that occurs in the dictionary. If you are trying to create a list of all the max value(s), then try something like this:
data = {'a':1, 'b':2, 'c': 3, 'd': 3}
max_value = data.get(max(data))
list_num_max_value = []
for letter in data:
if data.get(letter) == max_value:
list_num_max_value.append(max_value)
print (list_num_max_value)
Please let me know if that's not what you are trying to do and I will guide you through the right process.
