Let's say I have a function like this, to merge names in two lists:

def merge_name(list1="John",list2="Doe"):

    def merge(name1=list1,name2=list2):
        merge=name1 "-" name2
        data={"Merged":merge}
        return data
        
    d = pd.DataFrame()
    
    for i,j in [(i,j) for i in list1 for j in list2]:
        if i==j:
            d=d
        else:
            x = merge(name1=i,name2=j)
            ans=pd.DataFrame({"Merged":[x["Merged"]]})
            d=pd.concat([d,ans])    
        
    return d

What I am interested in are unique combinations, i.e, "John-Doe" and "Doe-John" are the same for my purposes. So if I run something like this:

names1=["John","Doe","Richard"]
names2=["John","Doe","Richard","Joana"]
df=merge_name(list1=names1,list2=names2)

I will get:

1. John-Doe
2. John-Richard
3. John-Joana
4. Doe-John
5. Doe-Richard
6. Doe-Joana
7. Richard-John
8. Richard-Doe
9. Richard-Joana

The groups in bold are all repetitions. Essentially, every time it comes to the next i, it creates n-1 repeated groups, with n being the position in names1. Is there a way to avoid this, like drop the top name in "list2" every time j becomes the last element in the list?

Thanks in advance.

I have tried to update list2 while in loop but obviously that does not work

CodePudding user response：

Below code can be useful

import pandas as pd
def merge_name(list1="John", list2="Doe"):
    merged=[]
    for i in list1:
        for j in list2:
            if (i!=j) and (f"{j} - {i}" not in merged):
                merged.append(f"{i} - {j}")
    df = pd.DataFrame(set(merged))
    return df


names1 = ["John", "Doe", "Richard"]
names2 = ["John", "Doe", "Richard", "Joana"]
df = merge_name(list1=names1, list2=names2)
print(df)

CodePudding user response：

Below is my solution with some explanations:

def combineName(listName):
  res = []
  for i in range(len(listName)):
    for j in range(i 1, len(listName)):
        res.append(listName[i]   "-"   listName[j])
  return res

names1=["John","Doe","Richard"]
names2=["John","Doe","Richard","Joana"]

listName = list(set(names1   names2))

print(listName)
print(combineName(listName))

First, you should create a simple list without repetitions. This way you only get unique elements in your list. To do this, I used a set. I take care to transform my set into a list because later I go through the structure in a given order, which is not supposed to be true for a set.

Secondly, the function creates all the combinations. There are two loops, and you notice that the second loop has a special range. Indeed, you do not want repetitions such as "John-Doe" and "Doe-John". Each combination is created at a unique time!