lush.py

#! /usr/bin/env python3

def round_volts(num, precision=4):
    return round(to_float(num), precision) # -- too slow
    # cut = precision+2
    # if num[0] == '-':
    #     cut += 1
    # return num[:cut]


def to_float(num):
    return float(num.replace(',', '.'))


def from_float(num):
    return str(num).replace('.', ',')


def read_files(names):
    all_raw_data = []

    for name in names:
        with open(name) as f:
            raw_data = f.read()

        all_raw_data.append(raw_data.splitlines())

    return all_raw_data

names = ['data1.csv', 'data2.csv']

raw_data1, raw_data2 = read_files(names)

with open('output.csv', mode='w') as f:

    for data1 in raw_data1:
        volt1, amp1 = data1.split(';')
        rounded_volt1 = round_volts(volt1)

        for data2 in raw_data2:
            volt2, amp2 = data2.split(';')
            rounded_volt2 = round_volts(volt2)

            if rounded_volt1 == rounded_volt2:
                row = '{};{}\n'.format(volt1, from_float(to_float(amp1)/to_float(amp2)))
                #print(row[:-1])
                f.write(row)
                break