Reference gotcha

[Ed Schofield]

Hi all,
This interested me:

a1 = a2 = {}
a1['blah'] = 1
a2 {'blah': 1}
a1 == a2

True


Whereas ...

False

So how should one create a robust alias for a numeric type?

This bit me when I was trying to do the following in a class:
def __init__(self, data):
a = self.a = {}
b = self.b = {}
c = self.c = 0

# and increment them here ...

Best regards,
Ed Schofield

 

[anton muhin]

Hi all,
This interested me:

a1 = a2 = {}
a1['blah'] = 1
a2

{'blah': 1}

True


Whereas ...

0

False

So how should one create a robust alias for a numeric type?

This bit me when I was trying to do the following in a class:
def __init__(self, data):
a = self.a = {}
b = self.b = {}
c = self.c = 0

# and increment them here ...

Best regards,
Ed Schofield

Standard trick is to use single element list or just a small object with
integer field.

hth,
anton.

 

[Paul Prescod]

Standard trick is to use single element list or just a small object with
integer field.

But why do that when "self." is already a small object with an integer
field?

Paul Prescod