dict problem...

wxPython Users
1

Hi people,
    A simple question:

I have a dict:

>> a = { 'element': 'red' }
>> b = a.copy()
>> a, b
({ 'element': 'red' }, { 'element': 'red' })
>> b['element'] = 'green'
>>a, b
({ 'element': 'red' }, { 'element': 'green' })

It's ok, very well, but....

>>> a = { 'button': {'color': 'red'} }
>>> a
{'button': {'color': 'red'}}
>>> b = a.copy()
>>> a, b
({'button': {'color': 'red'}}, {'button': {'color': 'red'}})
>>> a['button']['color'] = 'green'
>>> a,b
({'button': {'color': 'green'}}, {'button': {'color': 'green'}})

Why color value green change ever on "a" dict??? It's a bug??

thx

···

--
/\/\ariano Di Felice
Java/PHP/Python WEB/GUI Developer
http://www.marianodifelice.it
mariano.difelice@gmail.com
Tel. 0735 703735
Cell +39 339 6407211

2

dict.copy() does a shallow copy of the dictionary. in the second case you end up with the same color dictionary.
read more about it here:
http://en.wikipedia.org/wiki/Object_copy
for deep copy use the copy module. :slight_smile:

···

On Fri, May 30, 2008 at 9:11 PM, Mariano Di Felice mariano.difelice@gmail.com wrote:

Hi people,

A simple question:

I have a dict:

a = { ‘element’: ‘red’ }

b = a.copy()

a, b

({ ‘element’: ‘red’ }, { ‘element’: ‘red’ })

b[‘element’] = ‘green’

a, b

({ ‘element’: ‘red’ }, { ‘element’: ‘green’ })

It’s ok, very well, but…

a = { ‘button’: {‘color’: ‘red’} }

a

{‘button’: {‘color’: ‘red’}}

b = a.copy()

a, b

({‘button’: {‘color’: ‘red’}}, {‘button’: {‘color’: ‘red’}})

a[‘button’][‘color’] = ‘green’

a,b

({‘button’: {‘color’: ‘green’}}, {‘button’: {‘color’: ‘green’}})

Why color value green change ever on “a” dict??? It’s a bug??

thx

–

//\ariano Di Felice

Java/PHP/Python WEB/GUI Developer

http://www.marianodifelice.it

mariano.difelice@gmail.com

Tel. 0735 703735

Cell +39 339 6407211

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