title: Need help in the following to reduce the execution time
body: <p>This is just a part of the code, it takes around 5 min for each iteration ( for a single el) to execute. </p>
  
  <p>The length of fieldvalues is in the order of 1e6. I believe that multiple appends are eating away the time, Is there any alternative way for this ?</p>
  
  <pre><code>                PK2=[]
                  E_pl=[]
                  E_tot=[]            
  
                  for k in range(103,109):
  
                      PK2_k=[]
                      E_pl_k=[]
                      E_tot_k=[]
  
                      b=frame.fieldOutputs['SDV'+str(k)]
                      fieldValues=b.values
  
                      for v in fieldValues:
                           PK2_k.append(v.data)
                      PK2.append(PK2_k)
  
                      b=frame.fieldOutputs['SDV'+str(k+6)]
                      fieldValues=b.values
  
                      for v in fieldValues:
                           E_tot_k.append(v.data)             
                      E_tot.append(E_tot_k)
  
                      b=frame.fieldOutputs['SDV'+str(k+12)]
                      fieldValues=b.values
  
                      for v in fieldValues:
                           E_pl_k.append(v.data)                       
                      E_pl.append(E_pl_k)
  
                  t3=time.time()
                  print stepName,"All PK,E terms written",t3-at,"Sec"
  
                  PK2=np.array(PK2)   
                  PK2=np.transpose(PK2)   
  
                  E_tot=np.array(E_tot)   
                  E_tot=np.transpose(E_tot)   
  
                  E_pl=np.array(E_pl) 
                  E_pl=np.transpose(E_pl) 
  </code></pre>
  
  <p>Thanks in Advance !</p>