1

I'm not looking for an exact solution but looking for a keyword to research on. Not sure why but I really couldn't manage to find any examples for this very simple problem.

Lets assume I got 3 lists(could be more) that looks this:

l1=[x,y,z]
l2=[a,y,z,b]
l3=[a,b,c,d,e]

and what I'm trying to do is to have an comparison table looks like this:

    l1  l2  l3
a   0   1   1
b   0   1   1
c   0   0   1
d   0   0   1
e   0   0   1
x   1   0   0
y   1   1   0
z   1   1   0

lists can be in different length and they never have repetitions like:

l = [x,x,y]

again I'm not asking for someone to handle the task for me but I'm just looking for some keywords, advices, pseudo code to get things started.

erikci
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  • So you're trying to build a comparison table with a set of all the possible entries, and whether or not each list contains it? I suppose my clarification question would be, how do you intend to use this information? Because there's plenty of ways that you could do something like this, but how you approach can depend on your end goal. – user3832673 Mar 26 '21 at 23:45
  • Thanks for the question. Yes, I'm trying build table that I also don't know the possible entries. Most probably distinct sum of all lists will give me that. My end result is to find row and column values that contains most of the 1's. Actually, rows are cryptocurrencies and columns are exchanges. I'm trying to label each exchange so that when I make price comparison table, I know which coin is listed in which exchange. – erikci Mar 26 '21 at 23:53

2 Answers2

3

It may not be the fastest or the most efficient solution but I did it this way. I create a dictionary with keys being the values in all of the lists. Values being the which list the appear in. Then I print the headers (List names) and each key and values line by line. I am pretty sure there is a better way of doing this than my solution.

l1=["x","y","z"]
l2=["a","y","z","b"]
l3=["a","b","c","d","e"]

values = sorted(set(l1 + l2 + l3))

d = {}
for value in values:
    x = []
    if value in l1:
        x.append("1")
    else:
        x.append("0")
        
    if value in l2:
        x.append("1")
    else:
        x.append("0")
        
    if value in l3:
        x.append("1")
    else:
        x.append("0")
    d[value] = x

print(" "*3 + "l1 l2 l3")

for k in d:
    print(k + " "*2 + "  ".join(d[k]))
Kuzey
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0

After getting the clarification, if you want to pivot your data, why not try a dictionary, keyed on the row ID, and the value being a list of list IDs (since they're exchange, you should have some way to identify it)? As an example:

{ 'a': [l2, l3],
  'b': [l2, l3],
  'c': [l3],
...
}
user3832673
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