f 字符串未在列表内更新

Question

I'm trying to create the game Yahtzee in python, but I am having trouble putting the points in a table I made. The table is a list with each item corresponding to one row. Each item (meaning each row) is an f-string which retrieves a value from a dictionary inside curly brackets.

Later in the code, I update the value that is being called on in the row, and print the row. For some reason, the old value from the dictionary is the one that gets printed.

from random import randrange

def roll(saved):
    global roll
    roll = []
    for i in range(5 - len(saved)):
        roll.append(str(randrange(1,7)))
    global roll_og
    roll_og = roll
    roll.sort()
    print("Avaliable dice : " + ",".join(roll))

def avaliable_points():
#numbers
    global roll_og
    for i in range(1,7):
        if roll_og.count(str(i)) > 0:
            points[str(i)] = roll_og.count(str(i)) * i


def print_table(table):
    for i in table:
        print(i)


saved = []

points = {
    "1" : "",
    "2" : "",
    "3" : "",
    "4" : "",
    "5" : "",
    "6" : ""
}

avaliable_grid = [
     " _____________________________          _____________________________",
     "|           |Player 1|Player 2|        |           |Player 1|Player 2|",
     "|-----------|--------|--------|        |-----------|--------|--------|",
    f"|Ones       |{points[str(1)]}|        |        |3 of a Kind|        |        |",
    f"|-----------|--------|--------|        |-----------|--------|--------|",
    f"|Twos       |{points[str(2)]}|        |        |4 of a Kind|        |        |",
    f"|-----------|--------|--------|        |-----------|--------|--------|",
    f"|Threes     |{points[str(3)]}|        |        |Full House |        |        |",
    f"|-----------|--------|--------|        |-----------|--------|--------|",
    f"|Fours      |{points[str(4)]}|        |        |S. Straight|        |        |",
    f"|-----------|--------|--------|        |-----------|--------|--------|",
    f"|Fives      |{points[str(5)]}|        |        |L. Straight|        |        |",
    f"|-----------|--------|--------|        |-----------|--------|--------|",
    f"|Sixes      |{points[str(6)]}|        |        |Chance     |        |        |",
    "|-----------|--------|--------|        |-----------|--------|--------|",
    "|#############################|        |YAHTZEE    |        |        |",
    "|-----------|--------|--------|        |-----------|--------|--------|",
    f"|Sum        |        |        |        |#############################|",
    "|-----------|--------|--------|        |-----------|--------|--------|",
    f"|Bonus      |        |        |        |TOTAL SCORE|        |        |",
    " -----------------------------          ----------------------------- ",
    ]


roll(saved)
avaliable_points()
print(points)
print_table(avaliable_grid)    

The table I care about is the available_grid list, and the dictionary is the points dictionary. All the other functions in the code are the ones that determine how many points go into each slot in the table.

Avaliable dice : 1,2,2,4,6
{'1': 1, '2': 4, '3': '', '4': 4, '5': '', '6': 6}
 _____________________________          _____________________________
|           |Player 1|Player 2|        |           |Player 1|Player 2|
|-----------|--------|--------|        |-----------|--------|--------|
|Ones       ||        |        |3 of a Kind|        |        |
|-----------|--------|--------|        |-----------|--------|--------|
|Twos       ||        |        |4 of a Kind|        |        |
|-----------|--------|--------|        |-----------|--------|--------|
|Threes     ||        |        |Full House |        |        |
|-----------|--------|--------|        |-----------|--------|--------|
|Fours      ||        |        |S. Straight|        |        |
|-----------|--------|--------|        |-----------|--------|--------|
|Fives      ||        |        |L. Straight|        |        |
|-----------|--------|--------|        |-----------|--------|--------|
|Sixes      ||        |        |Chance     |        |        |
|-----------|--------|--------|        |-----------|--------|--------|
|#############################|        |YAHTZEE    |        |        |
|-----------|--------|--------|        |-----------|--------|--------|
|Sum        |        |        |        |#############################|
|-----------|--------|--------|        |-----------|--------|--------|
|Bonus      |        |        |        |TOTAL SCORE|        |        |
 -----------------------------          ----------------------------- 

I printed the dictionary after I changed it in order to check if it has indeed been changed.

Answer 1

The problem is that you're expecting the f strings to update when the points dictionary changes, but f strings are created immutably when interpreted. Look at this example:

>>> x = 10
>>> x_string = f"x is {x}"
>>> x_string
'x is 10'

>>> x = 20        # Change the value of x.
>>> x_string
'x is 10'

So one way to fix your problem is to define avaliable_grid within print_table() .

def print_table(points):
    available_grid = [ #...
                       #...
        ]
    for i in available_grid:
        print(i)

I also recommend passing in points so that you don't get mixed up with global variables.

By the way, since you only use the available_grid as a way to track the string, you can get the same result with a block string.

available_grid = f"""
 _____________________________          _____________________________
|           |Player 1|Player 2|        |           |Player 1|Player 2|
|-----------|--------|--------|        |-----------|--------|--------|
|Ones       |{points[str(1)]}|        |        |3 of a Kind|        |        |
|-----------|--------|--------|        |-----------|--------|--------|
|Twos       |{points[str(2)]}|        |        |4 of a Kind|        |        |
|-----------|--------|--------|        |-----------|--------|--------|
|Threes     |{points[str(3)]}|        |        |Full House |        |        |
|-----------|--------|--------|        |-----------|--------|--------|
|Fours      |{points[str(4)]}|        |        |S. Straight|        |        |
|-----------|--------|--------|        |-----------|--------|--------|
|Fives      |{points[str(5)]}|        |        |L. Straight|        |        |
|-----------|--------|--------|        |-----------|--------|--------|
|Sixes      |{points[str(6)]}|        |        |Chance     |        |        |
|-----------|--------|--------|        |-----------|--------|--------|
|#############################|        |YAHTZEE    |        |        |
|-----------|--------|--------|        |-----------|--------|--------|
|Sum        |        |        |        |#############################|
|-----------|--------|--------|        |-----------|--------|--------|
|Bonus      |        |        |        |TOTAL SCORE|        |        |
 -----------------------------          -----------------------------
"""