Passing Variables to Class Attributes
I've two files, one of which is a python (2.7) file with a class defined. I know how to create instances and the differences between class attributes and instance attributes. I know that upon creation of any instance, you pass variables based on what's defined in the constructor. But I'd like to pass a variable from the other file into my python file as a class attribute, not an instance attribute. Is this possible?
File #1 (Python 2.7):
class Controller:
"""
counter is my desired class attribute. But here, python
tells me GRID is not defined.
"""
counter = (GRID ** 2) # Gives a NameError.
def __init__(self, WIDTH, HEIGHT, GRID):
"""I'd like GRID to be a variable that's read from another file."""
self.WIDTH = WIDTH
self.HEIGHT = HEIGHT
self.GRID = GRID
File #2 ("Master" file to hold all constants and magic numbers):
WIDTH = 500
HEIGHT = 500
GRID = 4
controller = Controller(WIDTH, HEIGHT, GRID) # New Controller object.
When I try to define counter as a formula based on variable GRID, I get a NameError: GRID is not defined. Is there a way that I can define a class attribute -- counter in this case -- in terms of a variable?
Obviously I could just write counter = 4 ** 2, but I'd like to keep all constants and magic numbers in a single file, so I can update them only in one file as necessary.
python class
asked Nov 22 '18 at 23:10
WaterGuyWaterGuy
426
add a comment |
I've two files, one of which is a python (2.7) file with a class defined. I know how to create instances and the differences between class attributes and instance attributes. I know that upon creation of any instance, you pass variables based on what's defined in the constructor. But I'd like to pass a variable from the other file into my python file as a class attribute, not an instance attribute. Is this possible?
File #1 (Python 2.7):
class Controller:
"""
counter is my desired class attribute. But here, python
tells me GRID is not defined.
"""
counter = (GRID ** 2) # Gives a NameError.
def __init__(self, WIDTH, HEIGHT, GRID):
"""I'd like GRID to be a variable that's read from another file."""
self.WIDTH = WIDTH
self.HEIGHT = HEIGHT
self.GRID = GRID
File #2 ("Master" file to hold all constants and magic numbers):
WIDTH = 500
HEIGHT = 500
GRID = 4
controller = Controller(WIDTH, HEIGHT, GRID) # New Controller object.
When I try to define counter as a formula based on variable GRID, I get a NameError: GRID is not defined. Is there a way that I can define a class attribute -- counter in this case -- in terms of a variable?
Obviously I could just write counter = 4 ** 2, but I'd like to keep all constants and magic numbers in a single file, so I can update them only in one file as necessary.
python class
asked Nov 22 '18 at 23:10
WaterGuyWaterGuy
426
It makes no sense to take GRID as parameter, when at the same time it’s supposed to be a predefined constant. Define counter to be an INSTANCE variable instead and be happy.
– deets
Nov 22 '18 at 23:17
You just need animportstatement to use a constant in another module
– Robin Zigmond
Nov 22 '18 at 23:22
@deets Well I've other files (.py modules) that need to read the same exactcounter-- like a global variable, so if I putcounteras an instance attribute, how can other modules read/write the samecounter? Wouldn't there be separatecounterinstances in every module, every time I create aControllerobject in my other modules?
– WaterGuy
Nov 22 '18 at 23:48
Then pass the one object around.
– deets
Nov 23 '18 at 0:06
add a comment |
I've two files, one of which is a python (2.7) file with a class defined. I know how to create instances and the differences between class attributes and instance attributes. I know that upon creation of any instance, you pass variables based on what's defined in the constructor. But I'd like to pass a variable from the other file into my python file as a class attribute, not an instance attribute. Is this possible?
File #1 (Python 2.7):
class Controller:
"""
counter is my desired class attribute. But here, python
tells me GRID is not defined.
"""
counter = (GRID ** 2) # Gives a NameError.
def __init__(self, WIDTH, HEIGHT, GRID):
"""I'd like GRID to be a variable that's read from another file."""
self.WIDTH = WIDTH
self.HEIGHT = HEIGHT
self.GRID = GRID
File #2 ("Master" file to hold all constants and magic numbers):
WIDTH = 500
HEIGHT = 500
GRID = 4
controller = Controller(WIDTH, HEIGHT, GRID) # New Controller object.
When I try to define counter as a formula based on variable GRID, I get a NameError: GRID is not defined. Is there a way that I can define a class attribute -- counter in this case -- in terms of a variable?
Obviously I could just write counter = 4 ** 2, but I'd like to keep all constants and magic numbers in a single file, so I can update them only in one file as necessary.
python class
asked Nov 22 '18 at 23:10
WaterGuyWaterGuy
426
I've two files, one of which is a python (2.7) file with a class defined. I know how to create instances and the differences between class attributes and instance attributes. I know that upon creation of any instance, you pass variables based on what's defined in the constructor. But I'd like to pass a variable from the other file into my python file as a class attribute, not an instance attribute. Is this possible?
File #1 (Python 2.7):
class Controller:
"""
counter is my desired class attribute. But here, python
tells me GRID is not defined.
"""
counter = (GRID ** 2) # Gives a NameError.
def __init__(self, WIDTH, HEIGHT, GRID):
"""I'd like GRID to be a variable that's read from another file."""
self.WIDTH = WIDTH
self.HEIGHT = HEIGHT
self.GRID = GRID
File #2 ("Master" file to hold all constants and magic numbers):
WIDTH = 500
HEIGHT = 500
GRID = 4
controller = Controller(WIDTH, HEIGHT, GRID) # New Controller object.
When I try to define counter as a formula based on variable GRID, I get a NameError: GRID is not defined. Is there a way that I can define a class attribute -- counter in this case -- in terms of a variable?
Obviously I could just write counter = 4 ** 2, but I'd like to keep all constants and magic numbers in a single file, so I can update them only in one file as necessary.
python class
python class
asked Nov 22 '18 at 23:10
WaterGuyWaterGuy
426
asked Nov 22 '18 at 23:10
WaterGuyWaterGuy
426
asked Nov 22 '18 at 23:10
WaterGuyWaterGuy
426
asked Nov 22 '18 at 23:10
WaterGuyWaterGuy
426
asked Nov 22 '18 at 23:10
WaterGuyWaterGuy
426
426
It makes no sense to take GRID as parameter, when at the same time it’s supposed to be a predefined constant. Define counter to be an INSTANCE variable instead and be happy.
– deets
Nov 22 '18 at 23:17
You just need animportstatement to use a constant in another module
– Robin Zigmond
Nov 22 '18 at 23:22
@deets Well I've other files (.py modules) that need to read the same exactcounter-- like a global variable, so if I putcounteras an instance attribute, how can other modules read/write the samecounter? Wouldn't there be separatecounterinstances in every module, every time I create aControllerobject in my other modules?
– WaterGuy
Nov 22 '18 at 23:48
Then pass the one object around.
– deets
Nov 23 '18 at 0:06
add a comment |
It makes no sense to take GRID as parameter, when at the same time it’s supposed to be a predefined constant. Define counter to be an INSTANCE variable instead and be happy.
– deets
Nov 22 '18 at 23:17
You just need animportstatement to use a constant in another module
– Robin Zigmond
Nov 22 '18 at 23:22
@deets Well I've other files (.py modules) that need to read the same exactcounter-- like a global variable, so if I putcounteras an instance attribute, how can other modules read/write the samecounter? Wouldn't there be separatecounterinstances in every module, every time I create aControllerobject in my other modules?
– WaterGuy
Nov 22 '18 at 23:48
Then pass the one object around.
– deets
Nov 23 '18 at 0:06
It makes no sense to take GRID as parameter, when at the same time it’s supposed to be a predefined constant. Define counter to be an INSTANCE variable instead and be happy.
– deets
Nov 22 '18 at 23:17
It makes no sense to take GRID as parameter, when at the same time it’s supposed to be a predefined constant. Define counter to be an INSTANCE variable instead and be happy.
– deets
Nov 22 '18 at 23:17
You just need an
import statement to use a constant in another module– Robin Zigmond
Nov 22 '18 at 23:22
You just need an
import statement to use a constant in another module– Robin Zigmond
Nov 22 '18 at 23:22
@deets Well I've other files (.py modules) that need to read the same exact
counter -- like a global variable, so if I put counter as an instance attribute, how can other modules read/write the same counter? Wouldn't there be separate counter instances in every module, every time I create a Controller object in my other modules?– WaterGuy
Nov 22 '18 at 23:48
@deets Well I've other files (.py modules) that need to read the same exact
counter -- like a global variable, so if I put counter as an instance attribute, how can other modules read/write the same counter? Wouldn't there be separate counter instances in every module, every time I create a Controller object in my other modules?– WaterGuy
Nov 22 '18 at 23:48
Then pass the one object around.
– deets
Nov 23 '18 at 0:06
Then pass the one object around.
– deets
Nov 23 '18 at 0:06
add a comment |
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It makes no sense to take GRID as parameter, when at the same time it’s supposed to be a predefined constant. Define counter to be an INSTANCE variable instead and be happy.
– deets
Nov 22 '18 at 23:17
You just need an
importstatement to use a constant in another module– Robin Zigmond
Nov 22 '18 at 23:22
@deets Well I've other files (.py modules) that need to read the same exact
counter-- like a global variable, so if I putcounteras an instance attribute, how can other modules read/write the samecounter? Wouldn't there be separatecounterinstances in every module, every time I create aControllerobject in my other modules?– WaterGuy
Nov 22 '18 at 23:48
Then pass the one object around.
– deets
Nov 23 '18 at 0:06