M = [[0 for j in range(5)] for i in range(4)]
  for i in range(4):
     for j in range(5):
        M[i][j] = int(self.textEdit_1.toPlainText())

n = 1
  for i in range(4):
     for j in range(5):
        M[i][j] = exec('int(self.textEdit_{}.toPlainText())'.format(n))
        n += 1

n = 1
  for i in range(4):
     for j in range(5):
        M[i][j] = eval('int(self.textEdit_{}.toPlainText())'.format(n))
        n += 1

M = [[0 for j in range(5)] for i in range(4)]
n = 0
for i in range(4):
    for j in range(5):
        M[i][j] = listTextEdit[i+j+n]
    n += 4

[[1, 2, 3, 4, 5],
[6, 7, 8, 9, 10],
[11, 12, 13, 14, 15],
[16, 17, 18, 19, 20]]

import sys
from PyQt5.QtWidgets import *

class MainWindow(QMainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)

        for n in range(1, 21):
            exec('self.textEdit_{0} = QTextEdit("{0}")'.format(n))

        M = [[0 for j in range(5)] for i in range(4)]

        n = 1
        for i in range(4):
            for j in range(5):
                exec('M[i][j] =self.textEdit_{0}.toPlainText()'.format(n))
                n += 1

        for i in range(4):
            print(M[i])
            #label = QLabel("{}".format(i), self)
            line = ", ".join([ str(j) for j in M[i]])
            label = QLabel(line, self)
            label.move(20, i*10)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    w = MainWindow()
    w.show()
    sys.exit(app.exec_())