String length ... len(str)

[Jeff Wagner]

Can someone please explain the following to me:
[color=blue][color=green][color=darkred]
>>> str1 = "here"
>>> str2 = "here", "we", "are"
>>> len(str1)[/color][/color][/color]
4[color=blue][color=green][color=darkred]
>>> len(str2)[/color][/color][/color]
3

Why is len(str1) = 4 and len(str2) = 3?

If we were to say it's because the len() functions returns the number of elements in a string, then
len(str1) should be = 1

It's a little confusing.

Thanks,
Jeff

[Bernard Delmée]

Re: String length ... len(str)

> Why is len(str1) = 4 and len(str2) = 3?

Because str1 is a string whereas str2 is a tuple.
Both are sequences whose size is returned by len().
You probably meant str2 = "here" + "we" + "are"
If you ask "type(str2) " at the python prompt, you'll
see exactly what's going on.

Cheers,

Bernard.

[Jay O'Connor]

Re: String length ... len(str)

Jeff Wagner wrote:
[color=blue]
>Can someone please explain the following to me:
>
>
>[color=green][color=darkred]
>>>>str1 = "here"
>>>>str2 = "here", "we", "are"
>>>>len(str1)
>>>>
>>>>[/color][/color]
>4
>
>[color=green][color=darkred]
>>>>len(str2)
>>>>
>>>>[/color][/color]
>3
>
>Why is len(str1) = 4 and len(str2) = 3?
>
>If we were to say it's because the len() functions returns the number of elements in a string, then
>len(str1) should be = 1
>
>It's a little confusing.
>
>[/color]

str2 =is a tuple of three strings, not a concatenated string. So you
are getting the number if strings in the tuple, not the number of
characters in a longer string. You have to use join to concatenate the
strings with either join() or +
[color=blue][color=green][color=darkred]
>>> str2 = "here", "we", "are"
>>>
>>> str2[/color][/color][/color]
('here', 'we', 'are')[color=blue][color=green][color=darkred]
>>> type (str2)[/color][/color][/color]
<type 'tuple'>[color=blue][color=green][color=darkred]
>>> len (''.join (str2))[/color][/color][/color]
9[color=blue][color=green][color=darkred]
>>> str3 = "here" + "we" +"are"
>>> str3[/color][/color][/color]
'hereweare'[color=blue][color=green][color=darkred]
>>> len (str3)[/color][/color][/color]
9

[John Roth]

Re: String length ... len(str)


"Bernard Delmée" <bdelmee@advalv as.REMOVEME.be> wrote in message
news:3fce7c40$0 $1127$6c56d894@ feed0.news.be.e asynet.net...[color=blue][color=green]
> > Why is len(str1) = 4 and len(str2) = 3?[/color]
>
> Because str1 is a string whereas str2 is a tuple.
> Both are sequences whose size is returned by len().
> You probably meant str2 = "here" + "we" + "are"
> If you ask "type(str2) " at the python prompt, you'll
> see exactly what's going on.[/color]

Actually, you could also have said:

str2 = "here" "we" "are"

and gotten the concatination. Python automatically
concatinates string literals that come together. That
makes it a bit easier to split a literal across lines.
Admittedly, it's not the most obvious behavior,
although I believe it's faster since it happens in the
lexer (or the parser, but anyway at compile time).

John Roth[color=blue]
>
> Cheers,
>
> Bernard.
>[/color]

[Jeff Wagner]

Re: String length ... len(str)

Thanks for the info, it clears up a lot of confusion for me.

I was under the impression that:
str1 = "here" + "we" + "are" was the same as
str2 = "here" , "we" , "are" ...

the only difference being that the str2 was separated by a space. But str1 is a string, str2 is a
tuple. Cool ... who ever came up with the word tuple? That's a weird name.

I think this clears up a few other things I had questions with, too.

Thanks a lot,
Jeff

[Erik Max Francis]

Re: String length ... len(str)

Jeff Wagner wrote:
[color=blue]
> Thanks for the info, it clears up a lot of confusion for me.
>
> I was under the impression that:
> str1 = "here" + "we" + "are" was the same as
> str2 = "here" , "we" , "are" ...
>
> the only difference being that the str2 was separated by a space. But
> str1 is a string, str2 is a
> tuple.[/color]

Right. What probably confused you is that print acts like this:
[color=blue][color=green][color=darkred]
>>> print "one", "two", "three"[/color][/color][/color]
one two three

But this is only because print is a statement, and uses this as a
special form.
[color=blue]
> Cool ... who ever came up with the word tuple? That's a weird name.[/color]

It's derived from mathematics. A pair of items is a double, three items
is a triple, four is a quadruple, and n is an n-tuple.

--
Erik Max Francis && max@alcyone.com && http://www.alcyone.com/max/
__ San Jose, CA, USA && 37 20 N 121 53 W && &tSftDotIotE
/ \
\__/ Can I be your friend / 'Till the end
-- India Arie

[JanC]

Re: String length ... len(str)

Jeff Wagner <JWagner@hotmai l.com> schreef:
[color=blue]
> Cool ... who ever came up with the word tuple? That's a weird name.[/color]

I'm not sure but it may come from words like "quintuple" ...

--
JanC

"Be strict when sending and tolerant when receiving."
RFC 1958 - Architectural Principles of the Internet - section 3.9

[Dennis Lee Bieber]

Re: String length ... len(str)

JanC fed this fish to the penguins on Wednesday 03 December 2003 20:44
pm:
[color=blue]
>
>
> Jeff Wagner <JWagner@hotmai l.com> schreef:
>[color=green]
>> Cool ... who ever came up with the word tuple? That's a weird name.[/color]
>
> I'm not sure but it may come from words like "quintuple" ...
>[/color]
And is heavily used in formal relational database theory where it
equates to what most would call a "row" or even "record".

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