creating dictionary with nested loop

Question

I tried to create a dictionary with nested loops but failed. I do not know what's wrong:

dict={}
for i in range(0,4):
        node_1=str(i)
        for j in range(0,4):
            node_2=str(j)
            dict[node_1]=[node_2]         
print(dict)

It should have created:

{'0':['1','2','3'],'1':['0','2','3'],'2':['0','1','3']}

Please format your code as code. It's not readable now

IoaTzimas
– IoaTzimas

2020-09-23 11:28:12 +00:00
Commented Sep 23, 2020 at 11:28 — IoaTzimas
– IoaTzimas, Commented Sep 23, 2020 at 11:28

Moosa Saadat · Accepted Answer · 2020-09-23 11:32:02Z

2

In your code, you are overwriting the previous j value with the new j value. Instead, you should be appending it to a list.

mydict = {}
for i in range(0,4):
    node_1 = str(i)
    mydict[node_1] = [] # assign empty list
    for j in range(0,4):
        node_2 = str(j)
        mydict[node_1].append(node_2) # append in list

print(mydict)

Output:

{'0': ['0', '1', '2', '3'], '1': ['0', '1', '2', '3'], '2': ['0', '1', '2', '3'], '3': ['0', '1', '2', '3']}

Note: You should not name your variable dict which is the name for a built-in method.

answered Sep 23, 2020 at 11:32

Moosa Saadat

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Comments

Anton Pomieshchenko · Accepted Answer · 2020-09-23 11:32:17Z

1

Something like this?:

d = {}

for i in range(0,4):
        node_1=str(i)
        for j in range(0,4):
            node_2=str(j)
            if node_1 not in d:
                d[node_1] = []
            d[node_1].append(node_2)
print(d)

Please do not use dict for variable name.

answered Sep 23, 2020 at 11:32

Anton Pomieshchenko

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