Labelling words from the sentence they came from

Question

I have a dataframe with 3 columns namely 'word', 'pos-tag', 'label' . The words are originally from a text file.Now I would like to have another column 'sentences#' stating the index of sentences the words originally came from.

Current state:-
WORD POS-Tag Label
my   PRP$     IR
name  NN      IR 
is   VBZ      IR
ron  VBN      PERSON
.     .
my   PRP$     IR
name NN       IR
is   VBZ      IR
harry VBN     Person
.      .      IR
Desired state:-
Sentence#  WORD    Pos-Tag  Label
 1          My       PRP      IR
 1          name     NN       IR
 1           is      VBZ      IR
 1           ron     VBN      Person
 1            .       .       IR
 2            My     PRP      IR
 2            name   NN       IR
 2             is    VBZ      IR
 2           harry   VBN      Person
 2              .     .       IR

code I used till now:-

#necessary libraries
import pandas as pd
import numpy as np
import nltk 
import string
document=open(r'C:\Users\xyz\newfile.txt',encoding='utf8')
content=document.read()

sentences = nltk.sent_tokenize(content)
sentences = [nltk.word_tokenize(sent) for sent in sentences]
sentences = [nltk.pos_tag(sent) for sent in sentences]


flat_list=[]

# flattening a nested list
for x in sentences:
    for y in x:
        flat_list.append(y)

df = pd.DataFrame(flat_list, columns=['word','pos_tag']) 

#importing data to create the 'Label' column
data=pd.read_excel(r'C:\Users\xyz\pname.xlsx')
pname=list(set(data['Product']))

df['Label']=['drug' if x in fl else 'IR' for x in df['word']]

Answer 1

Just split your content into lines beforehand using split() with the appropriate punctuation marks. Store each line in some list, and then for index, line in enumerate(lines): do what you've normally done and also add index to your df.