I need to check two csv files containing coordinates, line by line, if any point from one file is close (less than 10 meters) in the second file, it returns True, unfortunately in the attached code, the second loop, I don't know why, is executed only once. Besides, maybe there is a faster way? Below is my code: def comparison_closeness_two_files(filename1, filename2): threshold_meters = 10/1000 # 10 meters file1 = open(filename1, 'r') file1 = csv.reader(file1, delimiter=',') file2 = open(filename2, 'r') file2 = csv.reader(file2, delimiter=',') for index, fc1 in enumerate(file1): if (len(fc1) != 4): continue lat1 = float(fc1[2]) lon1 = float(fc1[3]) for index, fc2 in enumerate(file2): if (len(fc2) != 4): continue lat2 = float(fc2[2]) lon2 = float(fc2[3]) distance = get_distance_between(lat1, lon1, lat2, lon2) if (distance <= threshold_meters): return True return False Continue reading...