add 'id' in pandas dataframe - regex

Question

I have a dataframe, the DOCUMENT_ID is the unique id which will contain multiple words from WORD column. I need to add ids for the each word within that document.
I need to add
DOCUMENT_ID WORD COUNT
0 262056708396949504 4
1 262056708396949504 DVD 1
2 262056708396949504 Girls 1
3 262056708396949504 Gone 1
4 262056708396949504 Gras 1
5 262056708396949504 Hurricane 1
6 262056708396949504 Katrina 1
7 262056708396949504 Mardi 1
8 262056708396949504 Wild 1
10 262056708396949504 donated 1
11 262056708396949504 generated 1
13 262056708396949504 revenues 1
15 262056708396949504 themed 1
17 262056708396949504 torwhore 1
18 262056708396949504 victims 1
20 262167541718319104 18
21 262167541718319104 CCUFoodMan 1
22 262167541718319104 CCUinvolved 1
23 262167541718319104 Congrats 1
24 262167541718319104 Having 1
25 262167541718319104 K 1
29 262167541718319104 blast 1
30 262167541718319104 blasty 1
31 262167541718319104 carebrighton 1
32 262167541718319104 hurricane 1
34 262167541718319104 started 1
37 262197573421502464 21
My expected outcome:
DOCUMENT_ID WORD COUNT WORD_ID
0 262056708396949504 4 1
1 262056708396949504 DVD 1 2
2 262056708396949504 Girls 1 3
3 262056708396949504 Gone 1
4 262056708396949504 Gras 1
.........
20 262167541718319104 18 1
21 262167541718319104 CCUFoodMan 1 2
22 262167541718319104 CCUinvolved 1 3
I have added for empty cells also but can be ignored.

Answer 1

Answer
df['WORD_ID'] = df.groupby(['DOCUMENT_ID']).cumcount()+1
Explanation
Let's build a DataFrame.
import pandas as pd
df = pd.DataFrame({'DOCUMENT_ID' : [262056708396949504, 262056708396949504, 262056708396949504, 262056708396949504, 262167541718319104, 262167541718319104, 262167541718319104], 'WORD' : ['DVD', 'Girls', 'Gras', 'Gone', 'DVD', 'Girls', "Gone"]})
df
DOCUMENT_ID WORD
0 262056708396949504 DVD
1 262056708396949504 Girls
2 262056708396949504 Gras
3 262056708396949504 Gone
4 262167541718319104 DVD
5 262167541718319104 Girls
6 262167541718319104 Gone
Given that your words are nested within unique Document_ID, we need a group by operation.
df['WORD_ID'] = df.groupby(['DOCUMENT_ID']).cumcount()+1
Output:
DOCUMENT_ID WORD WORD_ID
0 262056708396949504 DVD 1
1 262056708396949504 Girls 2
2 262056708396949504 Gras 3
3 262056708396949504 Gone 4
4 262167541718319104 DVD 1
5 262167541718319104 Girls 2
6 262167541718319104 Gone 3