Python occasional list index error when two integer dice held

Question

When I choose to hold two dice it will not always follow the script. It occurs at approximately line 50. Sometimes it doesn't even print the list. (As a side note- if anyone can simplify the code it would be much appreciated.) Can anybody help offer a solution and reason for the problem. (Script is below)

import random
points = 0
final = []
print("Welcome to Yahtzee")
print("Where there are closed questions answer lower case with 'y' or n'")
print("Please be aware that this a variation of the traditional game.\nShould you hold a number- you cannot 'unhold' it.\nIt has been added to your final roll for the round.")
print("Do not be tempted to hold onto a number you haven't rolled\n- this will not work and won't be added to your final score")

def roll_dice():
    global collection
    collection = []
    input("Press Enter to roll the first die")
    die_1 = random.randint(1,6)
    collection.append(die_1)
    print(die_1)

    input("Press Enter to roll the second die")
    die_2 = random.randint(1,6)
    collection.append(die_2)
    print(die_2)

    input("Press Enter to roll the third die")
    die_3 = random.randint(1,6)
    collection.append(die_3)
    print(die_3)

    input("Press Enter to roll the fourth die")
    die_4 = random.randint(1,6)
    collection.append(die_4)
    print(die_4)

   input("Press Enter to roll the fifth die")
   die_5 = random.randint(1,6)
   collection.append(die_5)
   print(die_5)
roll_dice()
print(collection)

yeno = input("Would you like to hold any dice? ")
if yeno == "n":
    input("This will mean re-rolling all the dice: proceeding...")
    del(collection)
    roll_dice()
    print(collection)
elif yeno == "y":
    no = input("How many dice would you like to hold: " )
    if no == "1":
        num1 = input("Enter the number you would like to keep: ")
        num1 = int(num1)
        for x in range(len(collection)-1):
            if collection[x] == num1:
                final.append(num1)
                del(collection[x])
                print(collection)
                print(final)
    if no == "2":
        num2 = input("Enter the first number you would like to keep: ")
        num2 = int(num2)
        num3 = input("Enter the second number you would like to keep: ")
        num3 = int(num3)
        for x in range(len(collection)-1):
            if collection[x] == num2:
                final.append(num2)
                del(collection[x])

        for x in range(len(collection)-1):
            if collection[x] == num3:
                final.append(num3)
                del(collection[x])
                print(collection)
                print(final)

Answer 1

Seems you would do well to read up on what list and the random module has to offer.

Below a suggested simple solution to generate one round of Yatzy.

NOTE: the solution uses formatted string literals so Python 3.6 or greater is needed.

#! /usr/bin/env python3

import sys
import random

greeting = """Welcome to Yatzy

Where there are closed questions answer lower case with 'y' or n'

When asked which dice to hold answer with a list of dice separated by
space.

At most 3 rounds per turn.  Between each turn decide what numbers to
keep before rolling again.

Please be aware that this a variation of the traditional game. Should
you hold a number- you cannot 'unhold' it. It has been added to your
final roll for the round.

Do not be tempted to hold onto a number you haven't rolled - this will
not work and won't be added to your final score.

"""
# Assume we have N dice.  There are 3 rounds per turn and between
# rounds the player chooses r numbers to keep.  The next round will
# then have N - r dice to roll.  After each turn the kept dice
# collection is displayed.
#
# The turn stops when 3 rounds have been played or when there are no
# more dice to roll or when the player decides to stop.


def play_one_turn(dice=5, turns=3):
    keep = []
    msg = "Dice to hold: "
    while turns and dice:
        turns -= 1
        print(f"Kept: {keep}")
        play = random.choices(range(1, 7), k=dice)
        print(f"Throw --> {play}")

        for h in map(int, input(msg).split()):
            if h in play:
                keep.append(h)
                dice -= 1
                play.remove(h)

        ask = "Another round? (yes/no) "
        if not input(ask).strip().upper().startswith('Y'):
            break
    return keep


if __name__ == "__main__":
    print(greeting)
    score = play_one_turn()
    print(f"Play result {score}")