import pandas as ps
data1 = ps.read_csv('L8.dat', header = None, sep='\s+',
                    dtype='float')
data2 = ps.read_csv('L16.dat', header = None, sep='\s+',
                    dtype='float')
data3 = ps.read_csv('L24.dat', header = None, sep='\s+',
                    dtype='float')
data4 = ps.read_csv('L32.dat', header = None, sep='\s+',
                    dtype='float')