How do I identify and label similar rows in a pandas data frame : I have a data set and I want to identify and label similar rows as such in python:

    [1, 1000]      [1]   
    [2, 10  ]      [2]  
    [2, 100 ]      [3]   
    [2, 10  ]  ->  [2]  
    [3, 1000]      [4]  
    [2, 100 ]      [3]  
    [2, 10  ]      [2]  