TypeError can only concatenate list not str to list

Question

I am trying to make an inventory program to use in an RPG  The program needs to be able to add and remove things and then add them to a list  This is what I have so far  inventory   quot sword quot   quot potion quot   quot armour quot   quot bow quot   print inventory  print  quot  ncommands  use  remove  and pickup  add  quot   selection input  quot choose a command  use pickup  quot    if selection   quot use quot       print inventory      remove input  quot What do you want to use   quot       inventory remove remove      print inventory   elif selection   quot pickup quot       print inventory      add input  quot What do you want to pickup   quot       newinv inventory str add      print newinv   When I run this and try to pick something up  I get this error  Traceback  most recent call last     File  quot H  Year 10 Computing A453 Python Programs inventory py quot   line 15  in  lt module gt      newinv inventory str add  TypeError  can only concatenate list  not  quot str quot   to list  Does any one have a fix for this  it would be greatly appreciated

User · Answer

I have a solution for this  First thing that add is already having a string value as input   function by default takes the input as string  Second thing that you can use append method to append value of add variable in your list  Please do check my code I have done some modification   -  1  You can enter command in capital or small or mix  2  If user entered wrong command then your program will ask to input command again inventory     quot sword quot   quot potion quot   quot armour quot   quot bow quot   print inventory  print  quot  ncommands   use  remove item  and pickup  add item  quot   selection input  quot choose a command  use pickup     quot   while True  if selection lower     quot use quot   print inventory  remove item input  quot What do you want to use   quot   inventory remove remove item  print inventory  break  elif selection lower     quot pickup quot         print inventory        add item input  quot What do you want to pickup   quot         inventory append add item        print inventory        break    else        print  quot Invalid Command  Please check your input quot         selection input  quot Once again choose a command  use pickup     quot

User · Answer

You can use   newinv inventory  add    but using append is better since it doesn t create a new list   inventory append add

User · Answer

Let me fix your code  inventory   sword    potion    armour    bow   print inventory  print   ncommands  use  remove  and pickup  add    selection input  choose a command  use pickup     if selection     use       print inventory      inventory remove input  What do you want to use          print inventory  elif selection     pickup       print inventory      add input  What do you want to pickup         newinv inventory  str add    use   str add    or list str add       print newinv    The error is you are adding string and list  you should use list or    to make the string become list type

User · Answer

That s not how to add an item to a string  This   newinv inventory str add    Means you re trying to concatenate a list and a string  To add an item to a list  use the list append   method   inventory append add   adds a new item to inventory print inventory   prints the new inventory   Hope this helps

User · Answer

I think what you want to do is add a new item to your list  so you have change the line newinv inventory str add  with this one    newinv   inventory append add    What you are doing now is trying to concatenate a list with a string which is an invalid operation in Python    However I think what you want is to add and delete items from a list  in that case your if else block should be   if selection   use       print inventory      remove input  What do you want to use         inventory remove remove      print inventory   elif selection   pickup       print inventory      add input  What do you want to pickup         inventory append add      print inventory    You don t need to build a new inventory list every time you add a new item

[python] TypeError: can only concatenate list (not "str") to list

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