DaveM schrieb:
On Sun, 27 Jul 2008 05:24:36 -0700 (PDT), alex23 <[EMAIL PROTECTED]> wrote:
On Jul 27, 10:13 pm, ssecorp <[EMAIL PROTECTED]> wrote:
I have seen somewhere that you can write something like:
x*x if x>10
but exactly that doesn't work and I can't get any variation to work.
It's called a ternary operator. The format is:
<label> = <true-value> if <condition> else <false-value>
I've seen the PERL saying/motto/boast, "There's more than one way to do it"
derided on more than one occasion on this group so what's the reason for
this additional way to put an if else statement on one line? Are "and" and
"or" constructions to produce the same effect not supported for this use?
You obviously aren't aware of the pitfalls regarding the mis-use of or
and and for this usage.
Try this:
>>> a = True
>>> b = 1
>>> c = 2
>>> a and b or c
1
>>> a = False
>>> a and b or c
2
>>> a = True
>>> b = None
>>> a and b or c
2
>>>
Afterwards I tried various formulae using "reduce" , falling foul
of the "=" catch on one occasion. Now I'm not a professional programmer, so
there may be good reasons for a single object to have multiple names in a
program, but it sounds like a recipe for disaster to me.
Can you tell us what you mean by "several names of one object"? You mean
this?
a = range(10)
b = a
id(a) == id(b)
? Passing references instead of values is an extremely important concept
of many languages, without it you would end up copying most of the time.
Getting back to the
list concatenation, I finally found the itertools.chain command which is the
most compact and fastest (or second fastest by a trivial amount, I can't
remember which). Along the way, I must have tried/used half a dozen methods,
...which brings me back my initial PERL comment. There's more than one way
to do it in Python, too.
Any non-trivial task has that property. I don't know enough perl to have
an example ready that shows something that python has only one way of
doing and perl has several.
But I *do* know that taking the python zen literally is fruitless.
Diez
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