Why does a randomizer act like a 'generator'-CodePudding

I am trying to make a simple rock paper scissors game on python

TypeError: unsupported operand type(s) for  : 'generator' and 'str'

This was the error message, that was given after I placed a randomizer in the code:

Traceback (most recent call last)

<ipython-input-4-dea4c40cfdcd> in <module>()
 49   if key == 'q':
 50     break
---> 51   player_score, comp_score = gameplay(player_score, comp_score)
 52   print('Score is: YOU ', player_score, ' - ', comp_score, ' COMPUTER')
 53   print('')

 <ipython-input-4-dea4c40cfdcd> in gameplay(player_score, comp_score)
 12 
 13   comp_move = moves[randomize]
 ---> 14   battle = key   '-'   comp_move
 15 
 16   comp_print = (word for position, word in ['rock', 'paper', 'scissors'] if position == randomize - 1)

What is this 'generator' object?? In google they say it is made from using a loop, so it is a kind of sequence, but didn't generate it with loop, rather than while loop. Is this loop the reason for the error? Moreover, I am not using the sequence of letters, but only a single letter from it, and I am calling it with its position number in the sequence?

Here is the code until the error:

 from random import randint

 player_score = 0
 comp_score = 0
 key = None

 # Setting the rules
 choices = {'r-s': 'rock breaks scissors', 'p-r': 'paper envelopes rock', 's-p': 'scissors cut paper'}
 moves = {1: 'r', 2: 'p', 3: 's'}

 def gameplay(player_score, comp_score):

   comp_move = moves[randomize]
   battle = key   '-'   comp_move

Here are more details about the code: the random number is initialized inside the while loop

while True:
  randomize = randint(1, 3)
  print('<r>ock, <p>aper or <s>cissors? Press any key to continue; <q> for exit')
  key = check_input()
  if key == 'q':
    break
  player_score, comp_score = gameplay(player_score, comp_score)
  print('Score is: YOU ', player_score, ' - ', comp_score, ' COMPUTER')
  print('')
  key = None

however, I am using a single variable not a sequence of variables here, or am I wrong?

As far as I have looked up for answers and explanations of the arrays in Python, I have found two different approaches to solve this, so far:

The first was by the means of the example from @John Coleman using 'for loop' and simplifying the expression with index of array:

items = ['rock', 'paper', 'scissors']

  for word in items:
    if items.index(word) == randomize - 1:
      print('Computer played: ', word)

The other approach was to improve the expression

item = (word for position, word in ['rock', 'paper', 'scissors'] if position == randomize - 1)

with the function 'enumerate':

  item = [word for position, word in enumerate(['rock', 'paper', 'scissors']) if position == randomize - 1]
  print('Computer played: ', item[0])

Actually, the problem appeared in the first place due to the lack of indexes of the arrays in Python, thus you have to find out how to make them by yourself.

Both of the given solutions work, so the topic could be considered 'closed'.

CodePudding user response：

Your check_input is overly complicated and inadvertently returns a generator object (one which would furthermore throw an error if you attempted to use it).

Instead, just do something like:

def check_input():
  while True:
    inputed = input('Press a key: <r>, <p>, <s>, or <q>')
    if inputed  in ['p', 'q', 'r', 's']:
        return inputed
    print('Wrong input! Press a key: <r>, <p>, <s>, or <q>')