Python Script that used to work, is now getting automatically killed in Ubuntu - pandas

Question

I was once able to run the below python script on my Ubuntu machine without the memory errors I was getting on windows.
import pandas as pd
import numpy as np
#create a pandas dataframe for each input file
dfs1 = pd.read_csv('s1.csv', encoding='utf-8', names=list(range(0,107)),dtype='string', na_filter=False)
dfs2 = pd.read_csv('s2.csv', encoding='utf-8', names=list(range(0,107)),dtype='string', na_filter=False)
dfr = pd.read_csv('r.csv' , encoding='utf-8', names=list(range(0,107)),dtype='string', na_filter=False)
#combine them into one dataframe
dfs12r = pd.concat([dfs1, dfs2, dfr],ignore_index=True)#withour ignore index the line numbers are not adjusted
# bow is "comming
wordlist=[]
for line in range(8052):
for row in range(106) :
#print(line,row,dfs12r[row][line])
if dfs12r[row][line] not in wordlist :
wordlist.append(dfs12r[row][line])
wordlist.sort()
#print(wordlist)
print(len(wordlist)) #12350
dfBOW = pd.DataFrame(np.zeros((len(dfs12r.index), len(wordlist))),dtype='int')
#create the dictionary
wordDict = dict.fromkeys(wordlist,'default')
counter=0
for word in wordlist :
wordDict[word] = counter
counter+=1
#print(wordDict)
#will start scanning every word from dfS12R and +1 the respective cell in dfBOW
for line in range(8052):
for row in range(107):
dfBOW[wordDict[dfs12r[row][line]]][line]+=1
Unfortunately, probably after some automatic Ubuntu updates I am now getting the simple message "KIlled", after trying to run the process without any further explanation.
Through simple print statements I know that the script is interrupted inside the for loop in the end.
I understand that I should be able to make the script more memory efficient, but I am also hoping for guidance on how to get Ubuntu able to run again the same script like they used to. (Through the TOP command I can see the all of my memory including the swap is being used while inside this loop)
Could paging have been disabled somehow after the updates? Any advice is welcome.
I still have 16GB of RAM, and use Ubuntu 20.04 (Specs are the same before and after the script stopped working). I use dual boot on the same SSD.
Below is the error I am getting from teh same script on windows :
Traceback (most recent call last):
File "D:\sharedfiles\Organised\WorkSpace\ptixiaki\github\ptixiaki\code\makingthedata\2.1 Approach (Same as 2 but turning all words to lowercase)\2.1_CSVtoDataframe\CSVtoBOW.py", line 60, in <module>
dfBOW[wordDict[dfs12r[row][line]]][line]+=1
File "D:\wandowsoftware\anaconda\envs\ptixiaki\lib\site-packages\pandas\core\series.py", line 1143, in __setitem__
self._maybe_update_cacher()
File "D:\wandowsoftware\anaconda\envs\ptixiaki\lib\site-packages\pandas\core\series.py", line 1279, in _maybe_update_cacher
ref._maybe_cache_changed(cacher[0], self, inplace=inplace)
File "D:\wandowsoftware\anaconda\envs\ptixiaki\lib\site-packages\pandas\core\frame.py", line 3950, in _maybe_cache_changed
self._mgr.iset(loc, arraylike, inplace=inplace)
File "D:\wandowsoftware\anaconda\envs\ptixiaki\lib\site-packages\pandas\core\internals\managers.py", line 1141, in iset
blk.delete(blk_locs)
File "D:\wandowsoftware\anaconda\envs\ptixiaki\lib\site-packages\pandas\core\internals\blocks.py", line 388, in delete
self.values = np.delete(self.values, loc, 0) # type: ignore[arg-type]
File "<__array_function__ internals>", line 5, in delete
File "D:\wandowsoftware\anaconda\envs\ptixiaki\lib\site-packages\numpy\lib\function_base.py", line 4555, in delete
new = arr[tuple(slobj)]
MemoryError: Unable to allocate 501. MiB for an array with shape (12234, 10736) and data type int32