Array design question

[Harvey Thomas]

Peter Slizik wrote:
> 
> Hi pythoners,
> 
>    after changing some messages in the 'Two dimensional 
> array' thread, 
> the discussion turned into somewhat philosophical debate on the way 
> Python works with arrays.
> 
>    I've been working with languages like PHP and Perl for some time. 
> Things so simple in PHP looks very difficult in Python (at 
> least for me).
> 
> Simple PHP code
> 
> a[1] = 'aaa'
> a[2] = 'bbb'
> a[3] = 'ccc'
> 
> will in Python read
> 
> a.append('aaa')
> a.append('bbb')
> a.append('ccc')
> 
> which is in my opinion uglier than PHP code.
> 
> I just don't understand, why Python doesn't allow to exceed array 
> boundaries. PHP and Perl would resize the array in this case.
> 
> Let's have a simple example. Suppose we have the file in format
> 7 "Text 1"
> 5 "Text 2"
> 3 "Text 3"
> ...
> ...
> 
> Our task is to read the content of the file into the array.
> 
> Simple PHP code
> 
> while( !eof() ) {
>      line = readline();
>      (number, text) = split(line);
>      array[number] = text;
> }
> 
> seems untranslatable into Python. The first attempt to store 
> an object 
> with index 7 into array before other 6 objects are stored there, will 
> cause an exception. But the numbers in the input file aren't in any 
> special order.
> 
> Is there any reason why Python designers chose this concept? 
> Wouldn't it 
>   be more convenient to have PHP-like arrays in Python too?
> 
> -- Peter

I think part of your problem is that you are comparing a PHP array with a Python list, whereas a PHP array is much more akin to a python dict. So an equivalent of your PHP code in Python is:

array = {}
for aline in afile:
    number, text = split(aline)
    array[number] = text

which bears more than a passing resemblance to your PHP code.

_____________________________________________________________________
This message has been checked for all known viruses by the MessageLabs Virus Scanning Service.