在Python中同一目录中的多个文件进行循环

Question

So I already tried to check other questions here about (almost) the same topic, however I did not find something that solves my problem.

Basically, I have a piece of code in Python that tries to open the file as a data frame and execute some eye tracking functions (PyGaze). I have 1000 files that I need to analyse and wanted to create a for-loop to execute my code on all the files automatically.

The code is the following:

os.chdir("/Users/Documents//Analyse/Eye movements/Python - Eye Analyse")

directory = '/Users/Documents/Analyse/Eye movements/R - Filtering Data/Filtered_data/Filtered_data_test'

for files in glob.glob(os.path.join(directory,"*.csv")):
    #Downloas csv, plot 
    df = pd.read_csv(files, parse_dates = True)
    #Plot raw data
    plt.plot(df['eye_x'],df['eye_y'], 'ro', c="red")
    plt.ylim([0,1080])
    plt.xlim([0,1920])
    #Fixation analysis 
    from detectors import fixation_detection 
    fixations_data = fixation_detection(df['eye_x'],df['eye_y'], df['time'],maxdist=25, mindur=100)
    Efix_data = fixations_data[1]
    numb_fixations = len(Efix_data) #number of fixations
    fixation_start = [i[0] for i in Efix_data] 
    fixation_stop = [i[1] for i in Efix_data] 
    fixation = {'start' : fixation_start, 'stop': fixation_stop}   
    fixation_frame = pd.DataFrame(data=fixation)
    fixation_frame['difference'] = fixation_frame['stop'] - fixation_frame['start']
    mean_fixation_time = fixation_frame['difference'].mean() #mean fixation time 
    final = {'number_fixations' : [numb_fixations], 'mean_fixation_time': [mean_fixation_time]} 
    final_frame = pd.DataFrame(data=final)
    #write everything in one document
    final_frame.to_csv("/Users/Documents/Analyse/Eye movements/final_data.csv")

The code is running (no errors), however : it only runs for the first file. The code is not ran for the other files present in the folder/directory. I do not see where my mistake is?

Answer 1

Your output file name is constant, so it gets overwritten with each iteration of the for loop. Try the following instead of your final line, which opens the file in "append" mode instead:

#write everything in one document
with open("/Users/Documents/Analyse/Eye movements/final_data.csv", "a") as f:
    final_frame.to_csv(f, header=False)