How to delete last item in list

Question

I have this program that calculates the time taken to answer a specific question  and quits out of the while loop when answer is incorrect  but i want to delete the last calculation  so i can call min   and it not be the wrong time  sorry if this is confusing   from time import time  q   input  What do you want to type     a       record      while a            start   time       a   input  Type         end   time       v   end-start     record append v      if a    q          print  Time taken to type name     2f   format v       else          break for i in record      print     2f  seconds   format i

User · Answer

list pop   removes and returns the last element of the list

User · Answer

If you have a list of lists  tracked output sheet in my case   where you want to delete last element from each list  you can use the following code   interim      for x in tracked output sheet interim append x  -1   tracked output sheet  interim

User · Answer

If I understood the question correctly  you can use the slicing notation to keep everything except the last item   record   record  -1    But a better way is to delete the item directly   del record -1    Note 1  Note that using record   record  -1  does not really remove the last element  but assign the sublist to record  This makes a difference if you run it inside a function and record is a parameter  With record   record  -1  the original list  outside the function  is unchanged  with del record -1  or record pop   the list is changed   as stated by  pltrdy in the comments   Note 2  The code could use some Python idioms  I highly recommend reading this  Code Like a Pythonista  Idiomatic Python  via wayback machine archive

User · Answer

You need   record   record  -1    before the for loop   This will set record to the current record list but without the last item  You may  depending on your needs  want to ensure the list isn t empty before doing this

User · Answer

you should use this  del record -1    The problem with   record   record  -1    Is that it makes a copy of the list every time you remove an item  so isn t very efficient

User · Answer

If you do a lot with timing  I can recommend this little  20 line  context manager    https   github com brouberol timer-context-manager   You code could look like this then      usr bin env python   coding  utf-8  from timer import Timer  if   name         main         a  record   None         while not a                with Timer   as t    everything in the block will be timed             a   input  Type             record append t elapsed s        drop the last item  makes a copy of the list       record   record  -1         or just delete it        del record -1      Just for reference  here s the content of the Timer context manager in full   from timeit import default timer  class Timer object           A timer as a context manager           def   init   self           self timer   default timer           measures wall clock time  not CPU time            On Unix systems  it corresponds to time time           On Windows systems  it corresponds to time clock      def   enter   self           self start   self timer     measure start time         return self      def   exit   self  exc type  exc value  exc traceback           self end   self timer     measure end time         self elapsed s   self end - self start   elapsed time  in seconds         self elapsed ms   self elapsed s   1000    elapsed time  in milliseconds

User · Answer

just simply use list pop   now if you want it the other way use   list popleft

[python] How to delete last item in list?

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