CODEWITHSUNDEEP
pythonstringlistdictionarycompare
toom
toom

Reputation: 231

Compare list items inside dictionary

Good day ! I am having some trouble comparing values inside lists that are inside a dictionary.

{'lst_4':['New York', 'Amsterdam', 'Berlin'],'lst_5':['New York', 'Brussels', 
Rome'],'lst_6':['Helsinki', 'Stockholm', Milan']}

The final goal is to compare the first item in each list, if they match I want to print which one it was. However I am having trouble comparing them because of the dict/listception.

My code so far:

x = 0
dct = {}
for row_cells in sheet.iter_rows(min_row=1, max_row=20):
    x += 1
    dct['lst_%s' %x] = []
    for cell in row_cells:
        if cell.value == None:
            break
        else:
            dct['lst_%s' %x].append(cell.value) 
    print("-------------------------------------------------")
    if not dct['lst_%s' %x]:
        break
    zin = dct['lst_%s' %x][0:]
    print(zin)

Any help, or pointers are much appreciated.

Cheers,

Upvotes: 0

Views: 118

Answers (3)

L3viathan
L3viathan

Reputation: 27283

I would use itertools.combinations for this:

from itertools import combinations

for one, two in combinations(dct, 2):
    if dct[one][0] == dct[two][0]:
        print("Both", one, "and", two, "have", dct[one][0])

Upvotes: 2

vvvvv
vvvvv

Reputation: 31670

If your goal is to detect if every list has the same first element, just do:

my_dict = {'lst_4':['New York', 'Amsterdam', 'Berlin'],
       'lst_5':['New York', 'Brussels', 'Rome'],
       'lst_6':['Helsinki', 'Stockholm', 'Milan']}

keys = list(my_dict.keys())

if all([my_dict[k][0] == my_dict[keys[0]][0] for k in keys]):
    print(my_dict[keys[0]][0])

In your example, there would be no output.

But if you want to find if 2 lists have the same first element, you could do something like:

my_dict = {'lst_4':['New York', 'Amsterdam', 'Berlin'],
           'lst_5':['New York', 'Brussels', 'Rome'],
           'lst_6':['Helsinki', 'Stockholm', 'Milan']}

keys = list(my_dict.keys())
for i, k1 in enumerate(keys):
    for j, k2 in enumerate(keys[i+1:]):
        if my_dict[k1][0] == my_dict[k2][0]:
            print(my_dict[k1][0])

In your case, the output is:

"New York"

You iterate over the lists to find if a couple of lists have the same first element.

Upvotes: 2

fleetingbytes
fleetingbytes

Reputation: 2992

You could try this:

d = {'lst_4':['New York', 'Amsterdam', 'Berlin'],'lst_5':['New York', 'Brussels', 'Rome'],'lst_6':['Helsinki', 'Stockholm', 'Milan']}


def findDuplicateFirstItem(dictionary):
    s = set()
    for value in dictionary.values():
        if value[0] not in s:
            s.add(value[0])
        else:
            print(value[0])

findDuplicateFirstItem(d)

>>>New York

Upvotes: 1

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