Dictionary Encoding Build

Problem

Build a dictionary encoding for a column of values.

The dictionary stores each distinct value once in first-appearance order, and the encoded column holds the dictionary index for every input value.

Return [dictionary, encoded_values].

Hint

The dictionary index is simply the number of distinct values seen so far.

case 1

in: [["b","a","b","c","a"]]

expected: [["b","a","c"],[0,1,0,2,1]]

case 2

in: [[]]

expected: [[],[]]

case 3

in: [[1,1]]

expected: [[1],[0,0]]

case 4

in: [["x","y","z"]]

expected: [["x","y","z"],[0,1,2]]

Starter codePython

def dictionary_encode(values):
    # Your code here
    pass

4 test cases · run your code against them in the editor