Comment puis-je réécrire les éléments suivants pour éviter une erreur "Imbrication des blocs"?

Question

Le code suivant génère

SystemError: too many statically nested blocks

import csv 
with open('complexdatset.csv','r'), open ('back.csv','w'), open ('buffer_overflow.csv','w'), open ('ftp_write.csv','w'), open ('guess_passwd.csv','w'), open ('imap.csv','w'), open ('ipsweep.csv','w'), open ('land.csv','w'), open ('loadmodule.csv','w'), open ('multihop.csv','w'), open ('neptune.csv','w'), open ('nmap.csv','w'), open ('perl.csv','w'), open ('phf.csv','w'), open ('pod.csv','w'), open ('portsweep.csv','w'), open ('rootkit.csv','w'), open ('satan.csv','w'), open ('smurf.csv','w'), open ('spy.csv','w'), open ('teardrop.csv','w'), open ('warezclient.csv','w'), open ('warezmaster.csv','w') as fin, back, buffer_overflow, ftp_write, guess_passwd, imap, ipsweep, land, loadmodule, multihop, neptune, nmap, perl, phf, pod, portsweep, rootkit, satan, smurf, spy, teardrop, warezclient, warezmaster: 
    writer0 = csv.writer(back, delimiter=',') 
    writer1 = csv.writer(buffer_overflow, delimiter=',') 
    writer2 = csv.writer(ftp_write, delimiter=',') 
    writer3 = csv.writer(guess_passwd, delimiter=',') 
    writer4 = csv.writer(imap, delimiter=',') 
    writer5 = csv.writer(land, delimiter=',') 
    writer6 = csv.writer(loadmodule, delimiter=',') 
    writer7 = csv.writer(multihop, delimiter=',') 
    writer8 = csv.writer(neptune, delimiter=',') 
    writer9 = csv.writer(nmap, delimiter=',') 
    writer10 = csv.writer(perl, delimiter=',') 
    writer11 = csv.writer(phf, delimiter=',') 
    writer12 = csv.writer(pod, delimiter=',') 
    writer13 = csv.writer(portsweep, delimiter=',') 
    writer14 = csv.writer(rootkit, delimiter=',') 
    writer15 = csv.writer(satan, delimiter=',') 
    writer16 = csv.writer(smurf, delimiter=',') 
    writer17 = csv.writer(spy, delimiter=',') 
    writer18 = csv.writer(teardrop, delimiter=',') 
    writer19 = csv.writer(warezclient, delimiter=',') 
    writer20 = csv.writer(warezmaster, delimiter=',') 
    for row in csv.reader(fin, delimiter=','): 
     if row[41] == 'back': 
      writer0.writerow(row) 
     elif row[41] == 'buffer_overflow': 
      writer1.writerow(row) 
     elif row[41] == 'ftp_write': 
      writer2.writerow(row) 
     elif row[41] == 'guess_passwd': 
      writer3.writerow(row) 
     elif row[41] == 'imap': 
      writer4.writerow(row) 
     elif row[41] == 'land': 
      writer5.writerow(row) 
     elif row[41] == 'loadmodule': 
      writer6.writerow(row) 
     elif row[41] == 'multihop': 
      writer7.writerow(row) 
     elif row[41] == 'neptune': 
      writer8.writerow(row) 
     elif row[41] == 'nmap': 
      writer9.writerow(row) 
     elif row[41] == 'perl': 
      writer10.writerow(row) 
     elif row[41] == 'phf': 
      writer11.writerow(row) 
     elif row[41] == 'pod': 
      writer12.writerow(row) 
     elif row[41] == 'portsweep': 
      writer13.writerow(row) 
     elif row[41] == 'rootkit': 
      writer14.writerow(row) 
     elif row[41] == 'satan': 
      writer15.writerow(row) 
     elif row[41] == 'smurf': 
      writer16.writerow(row) 
     elif row[41] == 'spy': 
      writer17.writerow(row) 
     elif row[41] == 'teardrop': 
      writer18.writerow(row) 
     elif row[41] == 'warezclient': 
      writer19.writerow(row) 
     elif row[41] == 'warezmaster': 
      writer20.writerow(row) 

Ma question est pourquoi faut-il générer cette erreur? J'ai cherché en ligne mais tous les exemples avaient des boucles imbriquées 20 niveaux profonds. Je n'ai pas beaucoup imbriqué le fichier I/O. Je fais juste des vérifications très poussées pour une variable et crée des fichiers à 2 niveaux de profondeur. Mon but était de créer des fichiers '.csv' individuels pour chacune des différentes classes de cet ensemble de données particulier. Y a-t-il aussi une meilleure façon de réécrire ceci afin que je puisse éviter SystemError?

Answer 1

utiliser un dictionnaire pour les options:

import csv 



with open('complexdatset.csv','r'), open ('back.csv','w'), open ('buffer_overflow.csv','w'), open ('ftp_write.csv','w'), open ('guess_passwd.csv','w'), open ('imap.csv','w'), open ('ipsweep.csv','w'), open ('land.csv','w'), open ('loadmodule.csv','w'), open ('multihop.csv','w'), open ('neptune.csv','w'), open ('nmap.csv','w'), open ('perl.csv','w'), open ('phf.csv','w'), open ('pod.csv','w'), open ('portsweep.csv','w'), open ('rootkit.csv','w'), open ('satan.csv','w'), open ('smurf.csv','w'), open ('spy.csv','w'), open ('teardrop.csv','w'), open ('warezclient.csv','w'), open ('warezmaster.csv','w') as fin, back, buffer_overflow, ftp_write, guess_passwd, imap, ipsweep, land, loadmodule, multihop, neptune, nmap, perl, phf, pod, portsweep, rootkit, satan, smurf, spy, teardrop, warezclient, warezmaster: 
    writer0 = csv.writer(back, delimiter=',') 
    writer1 = csv.writer(buffer_overflow, delimiter=',') 
    writer2 = csv.writer(ftp_write, delimiter=',') 
    writer3 = csv.writer(guess_passwd, delimiter=',') 
    writer4 = csv.writer(imap, delimiter=',') 
    writer5 = csv.writer(land, delimiter=',') 
    writer6 = csv.writer(loadmodule, delimiter=',') 
    writer7 = csv.writer(multihop, delimiter=',') 
    writer8 = csv.writer(neptune, delimiter=',') 
    writer9 = csv.writer(nmap, delimiter=',') 
    writer10 = csv.writer(perl, delimiter=',') 
    writer11 = csv.writer(phf, delimiter=',') 
    writer12 = csv.writer(pod, delimiter=',') 
    writer13 = csv.writer(portsweep, delimiter=',') 
    writer14 = csv.writer(rootkit, delimiter=',') 
    writer15 = csv.writer(satan, delimiter=',') 
    writer16 = csv.writer(smurf, delimiter=',') 
    writer17 = csv.writer(spy, delimiter=',') 
    writer18 = csv.writer(teardrop, delimiter=',') 
    writer19 = csv.writer(warezclient, delimiter=',') 
    writer20 = csv.writer(warezmaster, delimiter=',') 
    options = { 
     'back': writer0.writerow, 
     'buffer_overflow': writer1.writerow, 
     'ftp_write' : writer2.writerow, 
     'guess_passwd' : writer3.writerow, 
     'imap' :writer4.writerow, 
     'land':writer5.writerow, 
     'loadmodule':writer6.writerow, 
     'multihop':writer7.writerow, 
     'neptune':writer8.writerow, 
     'nmap':writer9.writerow, 
     'perl':writer10.writerow, 
     'phf':writer11.writerow, 
     'pod':writer12.writerow, 
     'portsweep':writer13.writerow, 
     'rootkit':writer14.writerow, 
     'satan':writer15.writerow, 
     'smurf':writer16.writerow, 
     'spy':writer17.writerow, 
     'teardrop':writer18.writerow, 
     'warezclient':writer19.writerow, 
     'warezmaster':writer20.writerow, 
    } 
    for row in csv.reader(fin, delimiter=','): 
     if row[41] in options.keys() : 
      options[row[41]](row) 

Answer 2

Votre open s sont essentiellement imbriquées, et vous avez 23 d'entre eux. Vous pouvez utiliser un contextlib.ExitStack() (contextlib2 dans Python 2.7) pour contenir plusieurs contextes, évitant ainsi l'imbrication.

Voir How to open more than 19 files in parallel (Python)? pour de bons exemples.