title: Python Pandas append Data-frame multiprocessor pool for loop to exist Data-frame
body: <p>i have dataframe called df3 with 5 columns</p>
  
  <p>and i am parsing dataframe tables from bittrex.com using multiprocessor pool to dataframe called df2</p>
  
  <p>i decreased processes to 2 only to simple my code as a test</p>
  
  <p>here is my code</p>
  
  <pre><code>import pandas as pd
  import json
  import urllib.request
  import os
  from urllib import parse
  import csv
  import datetime
  from multiprocessing import Process, Pool
  import time
  
  df3 = pd.DataFrame(columns=['tickers', 'RSIS', 'CCIS', 'ICH', 'SMAS'])
  tickers = ["BTC-1ST", "BTC-ADA"]
  
  def http_get(url):
      result = {"url": url, "data": urllib.request.urlopen(url, timeout=60).read()}
      return result
  
  urls = ["https://bittrex.com/Api/v2.0/pub/market/GetTicks?marketName=" + ticker + "&amp;tickInterval=thirtyMin" for ticker in tickers ]
  
  pool = Pool(processes=200)
  
  results = pool.map(http_get, urls)
  
  for result in results:
      j = json.loads(result['data'].decode())
      df2 = pd.DataFrame(data=j['result'])
  
      df2.rename(columns={'BV': 'BaseVolume', 'C': 'Close', 'H': 'High', 'L': 'Low', 'O': 'Open', 'T': 'TimeStamp',
                          'V': 'Volume'}, inplace=True)
  
      # Tenken-sen (Conversion Line): (9-period high + 9-period low)/2))
      nine_period_high = df2['High'].rolling(window=50).max()
      nine_period_low = df2['Low'].rolling(window=50).min()
      df2['tenkan_sen'] = (nine_period_high + nine_period_low) / 2
  
      # Kijun-sen (Base Line): (26-period high + 26-period low)/2))
      period26_high = df2['High'].rolling(window=250).max()
      period26_low = df2['Low'].rolling(window=250).min()
      df2['kijun_sen'] = (period26_high + period26_low) / 2
  
      TEN30L = df2.loc[df2.index[-1], 'tenkan_sen']
      TEN30LL = df2.loc[df2.index[-2], 'tenkan_sen']
      KIJ30L = df2.loc[df2.index[-1], 'kijun_sen']
      KIJ30LL = df2.loc[df2.index[-2], 'kijun_sen']
  
      if (TEN30LL &lt; KIJ30LL) and (TEN30L &gt; KIJ30L):
          df3.at[ticker, 'ICH'] = 'BUY'
      elif (TEN30LL &gt; KIJ30LL) and (TEN30L &lt; KIJ30L):
          df3.at[ticker, 'ICH'] = 'SELL'
      else:
          df3.at[ticker, 'ICH'] = 'NO'
  
      pool.close()
      pool.join()
      print(df2)
  </code></pre>
  
  <p>my question is about i always get error <code>NameError: name 'ticker' is not defined</code> which will get me mad 
  why i received this error In spite of i pre-defined ticker as a for loop in the line <code>urls = ["https://bittrex.com/Api/v2.0/pub/market/GetTicks?marketName=" + ticker + "&amp;tickInterval=thirtyMin" for ticker in tickers ]</code>
  and already python used it successfully.</p>
  
  <p>i googled for three days and tried several solutions without result. </p>
  
  <p>any ideas please ???!!!!</p>