Why is my function not updating a global variable consisting of nested lists?(python)
I'm creating a function to display the variable board. The else portion of the function display_board is supposed to change the elements of board to '-'. The first if statement is for another variable of my program called locations, which works fine.
When I call display_board it outputs the correct format, but it doesn't actually alter board, as seen when it prints board.
Any ideas why it's not working?
Sidenote: this is for an intro programming class in python, therefore, nested lists is about as advanced as my knowledge/scope of class goes.
board = [
[' ', ' ', ' '],
[' ', ' ', ' '],
[' ', ' ', ' ']
]
def display_board(board):
if board == locations:
for row in locations:
for column in row:
print(column, end=' ')
print()
# This chunk below is the important code that is not altering *board*
else:
for row in board:
for column in row:
if column == 'X':
print(column, end=' ')
elif column == 'O':
print(column, end=' ')
else:
column = '-'
print(column, end=' ')
print()
display_board(board)
print(board)
output:
- - -
- - -
- - -
[[' ', ' ', ' '], [' ', ' ', ' '], [' ', ' ', ' ']]
python function global-variables tic-tac-toe
asked Nov 21 '18 at 21:55
Colton FitzjarraldColton Fitzjarrald
1
add a comment |
I'm creating a function to display the variable board. The else portion of the function display_board is supposed to change the elements of board to '-'. The first if statement is for another variable of my program called locations, which works fine.
When I call display_board it outputs the correct format, but it doesn't actually alter board, as seen when it prints board.
Any ideas why it's not working?
Sidenote: this is for an intro programming class in python, therefore, nested lists is about as advanced as my knowledge/scope of class goes.
board = [
[' ', ' ', ' '],
[' ', ' ', ' '],
[' ', ' ', ' ']
]
def display_board(board):
if board == locations:
for row in locations:
for column in row:
print(column, end=' ')
print()
# This chunk below is the important code that is not altering *board*
else:
for row in board:
for column in row:
if column == 'X':
print(column, end=' ')
elif column == 'O':
print(column, end=' ')
else:
column = '-'
print(column, end=' ')
print()
display_board(board)
print(board)
output:
- - -
- - -
- - -
[[' ', ' ', ' '], [' ', ' ', ' '], [' ', ' ', ' ']]
python function global-variables tic-tac-toe
asked Nov 21 '18 at 21:55
Colton FitzjarraldColton Fitzjarrald
1
add a comment |
I'm creating a function to display the variable board. The else portion of the function display_board is supposed to change the elements of board to '-'. The first if statement is for another variable of my program called locations, which works fine.
When I call display_board it outputs the correct format, but it doesn't actually alter board, as seen when it prints board.
Any ideas why it's not working?
Sidenote: this is for an intro programming class in python, therefore, nested lists is about as advanced as my knowledge/scope of class goes.
board = [
[' ', ' ', ' '],
[' ', ' ', ' '],
[' ', ' ', ' ']
]
def display_board(board):
if board == locations:
for row in locations:
for column in row:
print(column, end=' ')
print()
# This chunk below is the important code that is not altering *board*
else:
for row in board:
for column in row:
if column == 'X':
print(column, end=' ')
elif column == 'O':
print(column, end=' ')
else:
column = '-'
print(column, end=' ')
print()
display_board(board)
print(board)
output:
- - -
- - -
- - -
[[' ', ' ', ' '], [' ', ' ', ' '], [' ', ' ', ' ']]
python function global-variables tic-tac-toe
asked Nov 21 '18 at 21:55
Colton FitzjarraldColton Fitzjarrald
1
I'm creating a function to display the variable board. The else portion of the function display_board is supposed to change the elements of board to '-'. The first if statement is for another variable of my program called locations, which works fine.
When I call display_board it outputs the correct format, but it doesn't actually alter board, as seen when it prints board.
Any ideas why it's not working?
Sidenote: this is for an intro programming class in python, therefore, nested lists is about as advanced as my knowledge/scope of class goes.
board = [
[' ', ' ', ' '],
[' ', ' ', ' '],
[' ', ' ', ' ']
]
def display_board(board):
if board == locations:
for row in locations:
for column in row:
print(column, end=' ')
print()
# This chunk below is the important code that is not altering *board*
else:
for row in board:
for column in row:
if column == 'X':
print(column, end=' ')
elif column == 'O':
print(column, end=' ')
else:
column = '-'
print(column, end=' ')
print()
display_board(board)
print(board)
output:
- - -
- - -
- - -
[[' ', ' ', ' '], [' ', ' ', ' '], [' ', ' ', ' ']]
python function global-variables tic-tac-toe
python function global-variables tic-tac-toe
asked Nov 21 '18 at 21:55
Colton FitzjarraldColton Fitzjarrald
1
asked Nov 21 '18 at 21:55
Colton FitzjarraldColton Fitzjarrald
1
asked Nov 21 '18 at 21:55
Colton FitzjarraldColton Fitzjarrald
1
asked Nov 21 '18 at 21:55
Colton FitzjarraldColton Fitzjarrald
1
asked Nov 21 '18 at 21:55
Colton FitzjarraldColton Fitzjarrald
1
1
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
Assigning to a variable doesn't modify the list element that the variable value was originally copied from. You need to assign to the list element itself. Change the second loop so you get the list indexes, then you can assign to that element.
for row in board:
for index, column in enumerate(row):
if column == 'X':
print(column, end=' ')
elif column == 'O':
print(column, end=' ')
else:
row[index] = '-'
print(row[index], end=' ')
print()
answered Nov 21 '18 at 22:02
BarmarBarmar
434k36259360
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53421003%2fwhy-is-my-function-not-updating-a-global-variable-consisting-of-nested-listspy%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
Assigning to a variable doesn't modify the list element that the variable value was originally copied from. You need to assign to the list element itself. Change the second loop so you get the list indexes, then you can assign to that element.
for row in board:
for index, column in enumerate(row):
if column == 'X':
print(column, end=' ')
elif column == 'O':
print(column, end=' ')
else:
row[index] = '-'
print(row[index], end=' ')
print()
answered Nov 21 '18 at 22:02
BarmarBarmar
434k36259360
add a comment |
Assigning to a variable doesn't modify the list element that the variable value was originally copied from. You need to assign to the list element itself. Change the second loop so you get the list indexes, then you can assign to that element.
for row in board:
for index, column in enumerate(row):
if column == 'X':
print(column, end=' ')
elif column == 'O':
print(column, end=' ')
else:
row[index] = '-'
print(row[index], end=' ')
print()
answered Nov 21 '18 at 22:02
BarmarBarmar
434k36259360
add a comment |
Assigning to a variable doesn't modify the list element that the variable value was originally copied from. You need to assign to the list element itself. Change the second loop so you get the list indexes, then you can assign to that element.
for row in board:
for index, column in enumerate(row):
if column == 'X':
print(column, end=' ')
elif column == 'O':
print(column, end=' ')
else:
row[index] = '-'
print(row[index], end=' ')
print()
answered Nov 21 '18 at 22:02
BarmarBarmar
434k36259360
Assigning to a variable doesn't modify the list element that the variable value was originally copied from. You need to assign to the list element itself. Change the second loop so you get the list indexes, then you can assign to that element.
for row in board:
for index, column in enumerate(row):
if column == 'X':
print(column, end=' ')
elif column == 'O':
print(column, end=' ')
else:
row[index] = '-'
print(row[index], end=' ')
print()
answered Nov 21 '18 at 22:02
BarmarBarmar
434k36259360
answered Nov 21 '18 at 22:02
BarmarBarmar
434k36259360
answered Nov 21 '18 at 22:02
BarmarBarmar
434k36259360
answered Nov 21 '18 at 22:02
BarmarBarmar
434k36259360
434k36259360
add a comment |
add a comment |
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53421003%2fwhy-is-my-function-not-updating-a-global-variable-consisting-of-nested-listspy%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
