Marc Tompkins wrote:
It can be a little hard to wrap your head around how Python handles
variables/objects; in other languages you create a variable and assign a
value to it, while in Python you create an object and assign a name to it -
the name can change while the object remains unchanged. Here's a very
simplified demo of what Dave is talking about:
[...]
It's extremely logical, but almost entirely backward from the way most other
languages do things. Possibly it's because Guido is Dutch.
Fortunately, that is untrue.
I'm not sure where the myth that "Python is different from other
languages" comes from. I suppose it is true only so far as *every*
language is different from any other language (otherwise they would be
the same language!). But Python is not so different from other common
languages.
In particular, I don't know of any language where assignment means
aliasing. Take the example Marc gave earlier:
t = 'this'
s = 'that'
group = [t, s]
print group # => "['this', 'that']
s = 'the other'
print group # => "['this', 'that']
I don't know of any language where the second item of group would now
equal 'the other'. Pascal certainly isn't one:
program example (input, output);
var
t,s: String(10);
group: array[1..2] of String(10);
begin
t:='this';
s:='that';
group[1]:=t;
group[2]:=s;
writeln(group[1], ' ', group[2]);
s:='the other';
writeln(group[1], ' ', group[2]);
end.
Running that program gives the equivalent output to Python:
this that
this that
PHP is the same. Using the PHP interactive shell:
php > $t = 'this';
php > $s = 'that';
php > $group[0] = $t;
php > $group[1] = $s;
php > print_r($group);
Array
(
[0] => this
[1] => that
)
php > $t = 'the other';
php > print_r($group);
Array
(
[0] => this
[1] => that
)
This myth of Python being radically different from other languages is
especially mysterious since many of the most popular and common modern
languages use *exactly* the same name binding execution model as Python,
e.g. Java and Ruby. (In the case of Java, that only applies to boxed
objects, and not unboxed low-level ints and similar. If this means
nothing to you, feel fortunate.)
--
Steven
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