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pythondictionaryfindmax
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Reputation: 69

how can i get largest key from dictionary?

maxValue = int(list(ab.keys())[i].split()[1])
for i in range(1, len(list(ab.keys()))):
    if maxValue > int(list(ab.keys())[i].split()[1]):
        maxValue = int(list(ab.keys())[i].split()[1])
sb = maxValue
maxValue = int(list(ab.keys())[i].split()[0])
for i in range(1, len(list(ab.keys()))):
    if maxValue > int(list(ab.keys())[i].split()[0]):
        maxValue = int(list(ab.keys())[i].split()[0])
sa = maxValue
maxValue = int(list(ab.keys())[i].split()[1])
for i in range(1, len(list(ab.keys()))):
    if maxValue < int(list(ab.keys())[i].split()[1]):
        maxValue = int(list(ab.keys())[i].split()[1])
bb = maxValue
maxValue = int(list(ab.keys())[i].split()[0])
for i in range(1, len(list(ab.keys()))):
    if maxValue < int(list(ab.keys())[i].split()[0]):
        maxValue = int(list(ab.keys())[i].split()[0])
ba = maxValue

i used to use this method, but i take too much time and i cannot use max(ab) cause my key look like this

ab = {"1 3":1, "2 3":2, "3 4":3}

Upvotes: 0

Views: 86

Answers (4)

Osadhi Virochana
Osadhi Virochana

Reputation: 1302

You can find largest key using,

max([i.replace(' ','') for i in ab.keys()])

If you need as int, use the following code.

max([int(i.replace(' ','')) for i in ab.keys()])

Upvotes: 1

Aviv Yaniv
Aviv Yaniv

Reputation: 6298

Finding the maximal number in the keys (based on the original code posted in the question, where keys are split, and maxValue is a number):


import itertools

ab = {"1 3":1, "2 3":2, "3 4":3}

# Splitting keys to numbers
# [['1', '3'], ['2', '3'], ['3', '4']]
x = [k.split() for k in ab.keys()]

# Chaining together the lists of keys numbers
# ['1', '3', '2', '3', '3', '4']
y = list(itertools.chain(*x))

# Finiding max key
# 4
print(max([int(z) for z in y]))

One-liner:

# 4
print(max([int(z) for z in list(itertools.chain(*[k.split() for k in ab.keys()]))]))

Upvotes: 0

Ajeet Mishra
Ajeet Mishra

Reputation: 382

I guess your question is your want to find largest key. So, if

ab = {"1 3":1, "2 3":2, "3 4":3}

then you are expecting "3 4" as the result. Is my understanding correct?

I am sharing a simplified conceptual program. See if this helps:

key_list = list(ab.keys())
key_list.sort()
print(key_list[-1])

Upvotes: 1

Rakesh
Rakesh

Reputation: 82755

I believe you need max with a custom key

Ex:

ab = {"1 3":1, "2 3":2, "3 4":3, "1 1": 4}
print(max(ab.items(), key=lambda x: tuple(map(int, x[0].split()))))

Output:

('3 4', 3)

Upvotes: 2

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