Emacs Calc: converting FROM Unix Time, unrecognized time zone

Emacs Calc: converting FROM Unix Time, unrecognized time zone

[Alan]

I am trying to use calc to convert a vector of unix times in a tide
table.  When using "t-U" to convert unix time, the following error is
received:

          Unrecognized time zone name: error

I changed the time zone (Gentoo GNU/Linux) by copying the posix GMT+10
zoneinfo file over /etc/localtime.  This seemed to make a difference
the first time---my timezone name is a little obscure, or so I
reasoned: "ChST" (I am on Saipan, N. Mariana Islands).

Also, I am uncertain how to use this command to convert FROM unix time
to something else.

Probably the time zone error is peripheral to my main problem, which
is just being able to convert a vector of a few thousand items by
grabbing them from a file into calc.

Thank you for any suggestions.  I am still reading the Fine Manual.

Alan Davis

Re: Emacs Calc: converting FROM Unix Time, unrecognized time zone

[Jay Belanger]

Alan <lngndvs@gmail.com> writes:

> I am trying to use calc to convert a vector of unix times in a tide
> table.  When using "t-U" to convert unix time, the following error is
> received:
>
>           Unrecognized time zone name: error
>
> I changed the time zone (Gentoo GNU/Linux) by copying the posix GMT+10
> zoneinfo file over /etc/localtime.  This seemed to make a difference
> the first time---my timezone name is a little obscure, or so I
> reasoned: "ChST" (I am on Saipan, N. Mariana Islands).

Yes; the Calc manual (under "Time Zones") has a list of time zones it
recognizes, and "ChST" is not one of them.  With no other information
to go on, Calc will look at the output of the "date" function to
determine the time zone.  You could bypass the "date" function and
tell Calc the timezone by setting Calc's `TimeZone' variable.

> Also, I am uncertain how to use this command to convert FROM unix time
> to something else.

`t U' will switch between unix time and date forms.  To convert a
vector of unix times into date forms, map 't U" across the vector:
`V M t U'

> Probably the time zone error is peripheral to my main problem, which
> is just being able to convert a vector of a few thousand items by
> grabbing them from a file into calc.

If the items are already grabbed, then it looks like `V M t U' is what
you want.

Jay

Re: Emacs Calc: converting FROM Unix Time, unrecognized time zone

[Alan]

On May 4, 3:27 am, Jay Belanger <jay.p.belan...@gmail.com> wrote:

> If the items are already grabbed, then it looks like `V M t U' is what
> you want.

It worked!  Ha!

I would like to be able to extract only decimal hours from the date
string
 "2007-05-05 14:30".  Is this possible?  I can easily do it by
grabbing
the minutes form and dividing by 60 in calc.   Of course, a more
direct
approach would be helpful.

I might offer that calc seems to have improved a great deal over the
past
12 or 13 years.   Also, the computer I am using is far and away faster
and more
powerful.

I am now struggling with how to set the time zone variable.  I guess I
can
use Sydney time, or GMT-10?

The calc manual says:
    "f your system does not have a suitable `date' command, you may
wish to put a `(setq var-TimeZone ...)' in your       Emacs
initialization file to set the time"

This variable is undocumented in emacs 23.0.0 (Gentoo GNU/Linux).

Thank you for the rapid response!

Alan Davis

Re: Emacs Calc: converting FROM Unix Time, unrecognized time zone

[Jay Belanger]

Alan <lngndvs@gmail.com> writes:
...
> I would like to be able to extract only decimal hours from the date
> string "2007-05-05 14:30".  Is this possible?  I can easily do it by
> grabbing the minutes form and dividing by 60 in calc.  Of course, a
> more direct approach would be helpful.

't P' (`calc-date-part') will get it for you.
Enter the date with algebraic notation:
<2007-05-05 14:30>
then, to get the hours, either `C-u 4 t P' or 
`t P', and then type `4' at the prompt (which will also tell you which
number to type to get the date parts: `1' for year,..., `4' for hours).

> I am now struggling with how to set the time zone variable.  I guess
> I can use Sydney time, or GMT-10?

A list of values that Calc recognizes is in the "Time Zones" section
of the Calc manual.  Perhaps the TimeZone variable should be made
customizable; for now, `s T' will take you to a buffer to set the
variable, and `s p TimeZone' will store the value permanently in your
calc initialization file.

> The calc manual says:
>     "f your system does not have a suitable `date' command, you may
> wish to put a `(setq var-TimeZone ...)' in your       Emacs
> initialization file to set the time"
>
> This variable is undocumented in emacs 23.0.0 (Gentoo GNU/Linux).

It's not documented as an Emacs lisp variable (although I guess it
should be), but it is documented as a Calc variable.  It is in the
variable index of the Calc manual under "TimeZone".  As a Calc
variable, it is "TimeZone", but to deal with it directly from elisp,
you need to use `var-TimeZone'.  (In general, the Calc variable `foo'
corresponds to the lisp variable `var-foo'.)

Jay

Re: Emacs Calc: converting FROM Unix Time, unrecognized time zone

[Alan]

On May 5, 1:31 am, Jay Belanger <jay.p.belan...@gmail.com> wrote:
>
> 't P' (`calc-date-part') will get it for you.
> Enter the date with algebraic notation:
> <2007-05-05 14:30>
> then, to get the hours, either `C-u 4 t P' or
> `t P', and then type `4' at the prompt (which will also tell you which
> number to type to get the date parts: `1' for year,..., `4' for hours).

This is very helpful.  It gives me HH:mm.  Is it possible to extract
HH.xx (hours and decimals) directly?


> It's not documented as an Emacs lisp variable (although I guess it
> should be), but it is documented as a Calc variable.  It is in the
> variable index of the Calc manual under "TimeZone".  As a Calc
> variable, it is "TimeZone", but to deal with it directly from elisp,
> you need to use `var-TimeZone'.  (In general, the Calc variable `foo'
> corresponds to the lisp variable `var-foo'.)

As far as I can find in the calc manual, I am told to set the
variable, but I have not been able to find out what is the format of
the variable?

For now I set GMT-10 by "s T', like this:
"GMT-10".

If I were to try to set ChST, the time zone more generally used on my
Island, would I have to edit also "calc-forms.el?  And what would I
need to enter?  There is no ChDT.

Your replies have been of inestimable help.  Thank you,

Alan

Re: Emacs Calc: converting FROM Unix Time, unrecognized time zone

[jay.p.belanger]

On May 5, 12:38 am, Alan <lngn...@gmail.com> wrote:
> On May 5, 1:31 am, Jay Belanger <jay.p.belan...@gmail.com> wrote:
> > Enter the date with algebraic notation:
> > <2007-05-05 14:30>
> > then, to get the hours, either `C-u 4 t P' or
> > `t P', and then type `4' at the prompt (which will also tell you which
> > number to type to get the date parts: `1' for year,..., `4' for hours).
>
> This is very helpful.  It gives me HH:mm.  Is it possible to extract
> HH.xx (hours and decimals) directly?

Are you using `t P 9' to get HMS form, then?  `t P 4' should just get
you HH, not HH:mm.
I don't think you can get HH.xx directly, but you could `t P 9' to get
hms form, and then
enter `M-x calc-from-hms' (`x', then `from-hms').

> As far as I can find in the calc manual, I am told to set the
> variable [var-TimeZone], but I have not been able to find out what is the format of
> the variable?
>
> For now I set GMT-10 by "s T', like this:
> "GMT-10". If I were to try to set ChST, the time zone more generally used on my
> Island, would I have to edit also "calc-forms.el?  And what would I
> need to enter?  There is no ChDT.

I suppose there should be more time zones added to `math-tzone-
names'.   You shouldn't edit calc-forms.el, but rather copy the value
of `math-tzone-names' from that file, and the appropriate values.  So
it should look something like
(setq math-tzone-names
   '(("UTC" 0 0)
 ...
( "YGT" 9 "YST" "YDT" ) ( "YST" 9 0 ) ( "YDT" 9 -1 )  ; Yukon



  ("ChST" 10 0)

Re: Emacs Calc: converting FROM Unix Time, unrecognized time zone

[jay.p.belanger]

Well, my last reply was sent prematurely.
Anyhow, your .emacs should contain

(setq math-tzone-names
  '(( "UTC" 0 0)
   ...
   ( "YGT" 9 "YST" "YDT" ) ( "YST" 9 0 ) ( "YDT" 9 -1 )  ; Yukon
   ("ChST" 10 0) ("ChDT" 10 -1) ("ChGT" 10 "ChST" "ChDT"))

or something like that (make sure about daylight saving time).

Jay