HELP : class and variables

[vincent delft]

Sorry if my question is stupid.
I've missed something with classes.
Can you explain the following ?
class test:
var1=1
var2=2
res=var1+var2

t=test()
print t.rest.var1=6
print t.res
??????????????????
I though that everithing is memory zones.
Why it's not 8 ?

Thanks

 

[Bruno Desthuilliers]

Sorry if my question is stupid.
I've missed something with classes.
Can you explain the following ?
class test:
var1=1
var2=2
res=var1+var2

t=test()
print t.res

Until here, t.var1 means test.var1 (class variable)

t.var1=6

From here, you created a new instance variable for object t, named
var1. It hides test.var1.

print t.res

What would you expect ?
1/ assigning to t.var1 does not modify test.var1
2/ modifiying test.var1 would not modify test.res anyway ! Guess why ?


Try this instead :.... def __init__(self):
.... # create instance variables
.... self.var1 = 1
.... self.var2 = 2
.... def res(self):
.... return self.var1 + self.var2
....8

Bruno

 

[Bertel Lund Hansen]

vincent delft skrev:

Can you explain the following ?
Yes.

class test:
var1=1
var2=2
res=var1+var2

t=test()
print t.res

t.var1=6
print t.res

Changing var1 does not change res.

You might like to make it a function instead:

class Test:
var1=1
var2=2
def res (self):
return self.var1+self.var2

t=Test()
t.var1=6
print t.res()

I learned in Java to give classes names with the first letter
capitalized. I find that a useful convention.