extract rows and filenames from multiple csv files

Question

I have multiple csv files with date as filename (20080101.csv to 20111031.csv) in a folder. The csv files have common headers. The csv file looks like this:

Answer 1

You could read in each file at a time. Read it line by line

files = ['20080101.csv', '20080102.csv', '20080103.csv'] #...etc
for f in files:
    file = open(f, 'r')
    for line in file:
        ray = line.split(';')
        if (ray[0].strip() == '1' and ray[1].strip() == '2'):
            fout = open('output.csv', 'a')
            fout.write(ray[0].strip() + ' ; ' + ray[1].strip() + ' ; ' + ray[2].strip() + ' ; ' + f + '\n')
            fout.close()
    file.close()

Tested and works. May need some slight modifications.