Is `wsample` a proper name for a function like this?

Satoru Logic

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Oct 10, 2012, 11:33:16 PM10/10/12

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I came across a function named `wsample` in a `utils` package of my workplace recently.

The "w" in `wsample` stands for `weighted`, and it randomly selects an element from a container according to relative weights of all the elements.

In most articles and codes I saw online, a function like this is often named `weighted_random_choice`, which sounds *correct* to me.
So when I saw this `wsample` function, I considered it a improper name.
Because `wsample`makes me think of `random.sample`, which returns a list of randomly generated elements, not a element.

Terry Reedy

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Oct 11, 2012, 12:33:35 AM10/11/12

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On 10/10/2012 11:33 PM, Satoru Logic wrote:
> I came across a function named `wsample` in a `utils` package of my
> workplace recently.
>
> The "w" in `wsample` stands for `weighted`, and it randomly selects
> an element from a container according to relative weights of all the
> elements.

I agree that wt_select for weighted select might be better for a sample
size of 1 ;-).

> In most articles and codes I saw online, a function like this is
> often named `weighted_random_choice`, which sounds *correct* to me.

Easier to understand, at least the first time, harder to write. Be glad
the author did not use 'ws' as would have once been common.

> So when I saw this `wsample` function, I considered it a improper
> name. Because `wsample`makes me think of `random.sample`, which
> returns a list of randomly generated elements, not a element.

--
Terry Jan Reedy

alex23

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Oct 11, 2012, 12:42:14 AM10/11/12

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On Oct 11, 1:33 pm, Satoru Logic <satorulo...@gmail.com> wrote:
> I came across a function named `wsample` in a `utils` package
> of my workplace recently.
>
> The "w" in `wsample` stands for `weighted`, and it randomly
> selects an element from a container according to relative
> weights of all the elements.
>

> So when I saw this `wsample` function, I considered it a improper name.

I tend to agree. I like descriptive names for functions that don't
assume familiarity. If you're unhappy with a function's name and
you're unable to modify the module it belongs to, you can always
rebind it yourself:

from utils import wsample as weighted_random_choice

If I'm then going to use that function heavily elsewhere, I _might_
rebind it, but always within the scope that is going to use the
abbreviated binding:

wrc = weighted_random_choice
<lots of lines of code using wrc>

Steven D'Aprano

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Oct 11, 2012, 2:29:37 AM10/11/12

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You can have a sample size of one.

wsample sounds fine to me. weighted_random_choice is okay too. It depends
whether you value brevity over explicitness. Explicit is good, but some
names are just too long.

If this were my code base, I would probably go for weighted_sample
without mentioning "random" in the name, the reasoning being that samples
are almost always random so explicitly saying so doesn't help much.

--
Steven

suzaku

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Oct 11, 2012, 2:44:42 AM10/11/12

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I think if a programmer has used the built-in `random` module before, he would expect a function with "sample" in its name to return a population sequence.

If a function is to return scalar value instead of sequence, I would expect it to be named "choice".

>
>
>
>
>
> --
>
> Steven

Steven D'Aprano

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Oct 11, 2012, 10:22:15 PM10/11/12

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On Wed, 10 Oct 2012 23:44:42 -0700, suzaku wrote:

> I think if a programmer has used the built-in `random` module before, he
> would expect a function with "sample" in its name to return a population
> sequence.

I have used the random module for about fifteen years, and I still write
random.sample when I need to use random.choice.

In statistics, probability, and plain English, a sample can be a single
item: that's why we can say "a sample" or "two samples".

> If a function is to return scalar value instead of sequence, I would
> expect it to be named "choice".

And I wouldn't. But what do I care? I'm never going to use the code
you're talking about, so call it "sasquatch" if you like, it's no skin
off my nose.

:)

--
Steven

suzaku

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Oct 11, 2012, 10:48:19 PM10/11/12

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On Friday, October 12, 2012 10:22:16 AM UTC+8, Steven D'Aprano wrote:
> On Wed, 10 Oct 2012 23:44:42 -0700, suzaku wrote:
>
>
>
> > I think if a programmer has used the built-in `random` module before, he
>
> > would expect a function with "sample" in its name to return a population
>
> > sequence.
>
>
>
> I have used the random module for about fifteen years, and I still write
>
> random.sample when I need to use random.choice.
>
>
>
> In statistics, probability, and plain English, a sample can be a single
>
> item: that's why we can say "a sample" or "two samples".

Thanks for sharing your experience.

As I'm not a native speaker of English,
when I learned that `random.choice` return single item,
and `random.sample` return a sequence of items,
I thought that the behaviour is determined by their definitions.