multi-column factorize in pandas

Question

The pandas factorize function assigns each unique value in a series to a sequential, 0-based index, and calculates which index each series entry belongs to.

Answer 1

I am not sure if this is an efficient solution. There might be better solutions for this.

arr=[] #this will hold the unique items of the dataframe
for i in df.index:
   if list(df.iloc[i]) not in arr:
      arr.append(list(df.iloc[i]))

so printing the arr would give you

>>>print arr
[[1,1],[1,2],[2,2]]

to hold the indices, i would declare an ind array

ind=[]
for i in df.index:
   ind.append(arr.index(list(df.iloc[i])))

printing ind would give

 >>>print ind
 [0,1,2,2,1,0]