CODEWITHSUNDEEP
pythonloopsfor-loopsubprocessstdout
Tolga Varol
Tolga Varol

Reputation: 1236

What is Wrong with the for Loops

I can't get an output from this code, it is just looping infinitely I guess, it has to readlines and append those lines to the list named data, but it doesn't give an output, what have I done wrong? Any suggestions will be appreciated, thanks in advance.

import os
import subprocess
import commands

command = ['sudo', 'iwlist', 'wlan0', 'scan']
output = subprocess.Popen(command, stdout=subprocess.PIPE).stdout.readlines()
data = []
for item in output:
      if item.strip().startswith('ESSID:'):
           data = (item.lstrip('ESSID:').rstrip('\n'))
      for item in output:
            if item.strip().startswith('Quality:'):
                 data.append('Quality:')
            for item in output:
                  if item.strip().startswith('Pairwise:'):
                       data.append('Pairwise:')
                       print data

Upvotes: 1

Views: 137

Answers (1)

Anshul Goyal
Anshul Goyal

Reputation: 76887

Try the code below, I don't think you need multiple for loops.

Also, the command iwlist works without sudo permissions as well, so you should cut it out (since you won't be able to enter the sudo password with subprocess.PIPE)

I've also removed os, commands modules which though imported are not being used anywhere.

import subprocess

command = ['iwlist', 'wlan0', 'scan']
output = subprocess.Popen(command, stdout=subprocess.PIPE).stdout.readlines()
data = []
for item in output:
    if item.strip().startswith('ESSID:'):
         data.append([item.lstrip('ESSID:').rstrip('\n')])
    if item.strip().startswith('Quality:'):
        data.append('Quality:')
    if item.strip().startswith('Pairwise:'):
        data.append('Pairwise:')
print data

EDIT

Since you want to read each of the connections, try this one

import subprocess

command = ['sudo', '-S', 'iwlist', 'wlan0', 'scan']
output = subprocess.Popen(command, stdout=subprocess.PIPE).stdout.read()
data = []
for cell_item in output.split("Cell"):
    data_item = []
    for line in cell_item.split("\n"):
        if any(item in line for item in ["ESSID", "Quality", "Pairwise"]):
            data_item.append(line.strip())
    if data_item:
        data.append(data_item)
print data

The trick here is to split the output by cells first (based on output of iwlist on my system), and then, within each of the cell, you can check for Quality, Pairwise, ESSID.

Upvotes: 3

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