Everywhere I research gives the code;

# Get the first column and first row of table
self.tableWidget.itemAt(0,0).text()

Actually it works. I can get the value of first column and first row.

# Try to get all 6 cells values
self.tableWidget.itemAt(0,0).text()
self.tableWidget.itemAt(0,1).text()
self.tableWidget.itemAt(0,2).text()
self.tableWidget.itemAt(1,0).text()
self.tableWidget.itemAt(1,1).text()
self.tableWidget.itemAt(1,2).text()

But when I try to get other 5 cells values, it returns same value.

After some investigation, I found that that itemAt(x,y) values are not indexes. They are pixels.
I try to figure out how it works heuristicly.

# this may gives second rows item
self.tableWidget.itemAt(20,40).text()

Isn't there a way for access the cells other than this weird method?

Actually I don't want to access the cells with pixels, I just want to access them via index.