Compare fields from two csv files

[Pedroski55]

I never have anything to do with large amounts of data. My longest csv is only about 200 lines long.

Don't know how you could compare each line without calling each line!

Maybe I have not understood what you really want.

def myApp():
    # read in 2 big old .csv files (in my case tiny)
    path2csv1 = '/home/pedro/myPython/csv/csv1.csv'
    with open(path2csv1) as CSV1:
        list1 = CSV1.readlines()

    path2csv2 = '/home/pedro/myPython/csv/csv2.csv'
    with open(path2csv2) as CSV2:
        list2 = CSV2.readlines()        

    # first problem: the lists are not equal in length?
    if not len(list1) == len(list2):
        print('Problem, the lists are not the same length ... ')
    
    difference = 0   
    if len(list1) > len(list2):
        difference = len(list1) - len(list2)
    if len(list2) > len(list1):
        difference = len(list2) - len(list1)

    dlist = []
    for d in range(0, difference):
        dlist.append('X')

    if len(list1) > len(list2):
        list2 = list2 + dlist
    if len(list2) > len(list1):
        list1 = list1 + dlist   

    # check lengths
    if not len(list1) == len(list2):
        print('Problem, the lists are not the same length ... ')
    elif len(list1) == len(list2):
        print('The lists now have the same length, we can proceed ... '

    # generate a list of tuples of dissimilar lines    
    def getDisimilar_lines():
        for i in range(len(list1)):
            if list1[i] != list2[i]:
                yield (list1[i], list2[i], f'line_{i}')

    not_the_same = getDisimilar_lines()

    for t in not_the_same:
            print(t)    
    # easy to write to Excel from here