Help needed with merging two CSV files

[paul18fr]

You may also use Pandas and Numpy to deal with huge files; just an example here bellow

import pandas as pd
import numpy as np
import os

Path=str(os.getcwd())
CsvFile1='data1.csv' 
CsvFile2='data2.csv' 

# if you've a header (if not put it to False)
Header=True

# First csv file reading
File1=pd.read_csv(Path + '/' + CsvFile1, header=None, delimiter=';')
if Header : File1=File1.drop([0], axis=0)
Array1=File1.to_numpy(dtype=float)

# second csv file reading
File2=pd.read_csv(Path + '/' + CsvFile2, header=None, delimiter=';')
if Header : File2=File2.drop([0], axis=0)
Array2=File2.to_numpy(dtype=float)

# concatenation: you must have the same number of rows, but may have different number of columns
Concat=np.hstack((Array1, Array2))

# write a "like" csv file; remove fmt for the highest accuracy %.18e
# np.savetxt(Path + '/concat.csv', Concat, delimiter=';', fmt='%f')
np.savetxt(Path + '/concat.csv', Concat, delimiter=';')