| Re: Adding Text/Equations to Plots [message #65698] |
Mon, 16 March 2009 12:54  |
Jean H.
Messages: 472
Registered: July 2006
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Senior Member |
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doh, I hate when I receive the other poster messages 1/2 hour late...
so, sorry for the repetition..
Jean H. wrote:
> Heather wrote:
>
>> IDL> numbers=findgen(10)
>> IDL> string="This is a number: numbers(6)"
>> IDL> print, string
>> This is a number: numbers(6)
>
>> Any advice would be greatly appreciated, but I'm fairly new to the
>> world of IDL, so please use "simple" explanations!
>> Thanks,
>> Heather
>
> Heather,
> You can do string concatenation and conversion
>
> print, "this is a number " + string(numbers[6])
>
> you can also have more control... remove the blanks:
>
> print, "this is a number " + strtrim(numbers[6],2)
>
> or even add formats:
> print, "this is a number " + string(numbers[6],format = '(I)')
>
> and with no blanks
>
> print, "this is a number " + strtrim(string(numbers[6],format = '(I)'),2)
>
> Jean
> PS: replace print, by text = if you want to save the string
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| Re: Adding Text/Equations to Plots [message #65700 is a reply to message #65698] |
Mon, 16 March 2009 13:16  |
Michael Galloy
Messages: 1114
Registered: April 2006
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Senior Member |
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Jean H. wrote:
> Heather wrote:
>
>> IDL> numbers=findgen(10)
>> IDL> string="This is a number: numbers(6)"
>> IDL> print, string
>> This is a number: numbers(6)
>
>> Any advice would be greatly appreciated, but I'm fairly new to the
>> world of IDL, so please use "simple" explanations!
>> Thanks,
>> Heather
>
> Heather,
> You can do string concatenation and conversion
>
> print, "this is a number " + string(numbers[6])
>
> you can also have more control... remove the blanks:
>
> print, "this is a number " + strtrim(numbers[6],2)
>
> or even add formats:
> print, "this is a number " + string(numbers[6],format = '(I)')
>
> and with no blanks
>
> print, "this is a number " + strtrim(string(numbers[6],format = '(I)'),2)
>
> Jean
> PS: replace print, by text = if you want to save the string
I have been steering away from string concatenation and using C format
strings for almost everything lately:
IDL> print, numbers[6], format='(%"This is a number: %f.")'
I think the code is a more readable. Of course, then you have to learn
the available format codes (with C and Fortran versions to choose from).
The STRING command accept the same FORMAT if you want to pass the string
to a keyword of XYOUTS, PLOT, etc.
By the way, I hate that I have to type five extra characters to get
C-style format codes. Maybe a cformat option to COMPILE_OPT to switch
the default format to C-style? (Yes, I know "cformat" is seven characters.)
Mike
--
www.michaelgalloy.com
Associate Research Scientist
Tech-X Corporation
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| Re: Adding Text/Equations to Plots [message #65701 is a reply to message #65698] |
Mon, 16 March 2009 12:45 |
Jean H.
Messages: 472
Registered: July 2006
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Senior Member |
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Heather wrote:
> IDL> numbers=findgen(10)
> IDL> string="This is a number: numbers(6)"
> IDL> print, string
> This is a number: numbers(6)
> Any advice would be greatly appreciated, but I'm fairly new to the
> world of IDL, so please use "simple" explanations!
> Thanks,
> Heather
Heather,
You can do string concatenation and conversion
print, "this is a number " + string(numbers[6])
you can also have more control... remove the blanks:
print, "this is a number " + strtrim(numbers[6],2)
or even add formats:
print, "this is a number " + string(numbers[6],format = '(I)')
and with no blanks
print, "this is a number " + strtrim(string(numbers[6],format = '(I)'),2)
Jean
PS: replace print, by text = if you want to save the string
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| Re: Adding Text/Equations to Plots [message #65702 is a reply to message #65701] |
Mon, 16 March 2009 12:33 |
Heather
Messages: 2
Registered: March 2009
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Junior Member |
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On Mar 16, 1:26 pm, David Fanning <n...@dfanning.com> wrote:
> Heather writes:
>> I'm hoping someone can help me figure out a way to add equations to a
>> plot. I used POLY_FIT to find the coefficients of a line for my data,
>> and plotted that line. I really want to add the equation of that line
>> to my plot.
>
>> I thought I could use legend.pro (a routine I found at
>> http://astro.uni-tuebingen.de/software/idl/astrolib/plot/leg end.pro
>> that I am already calling in my routine anyhow), but that requires the
>> input "items" be a string. And I couldn't figure out how to create a
>> string that would call the elements of the array in which the
>> coefficients are.
>> (This is what I tried:
>> IDL> numbers=findgen(10)
>> IDL> string="This is a number: numbers(6)"
>> IDL> print, string
>> This is a number: numbers(6)
>
>> Clearly not what I want. And I can't do something like:
>> IDL> string1="This is a number: "
>> IDL> print, string1, numbers(6)
>> This is a number: 6.00000
>
>> because what it will actually look like to the legend.pro routine is:
>> IDL> string2="This is a number: " numbers(6)
>
>> string2="This is a number: " numbers(6)
>> ^
>> % Syntax error.
>
>> Any advice would be greatly appreciated, but I'm fairly new to the
>> world of IDL, so please use "simple" explanations!
>
> "Simple explanations"!? Do you see what the world is
> coming to?
>
> OK, here is a simple explanation. What you want to
> do is concatenate strings. That is a big word that
> means "string them together like beads on a string".
> Whoops! Two different meanings of "string" here. :-(
>
> OK, looks like you maybe know what a string is in
> computer-speak. What you need to know, in a nutshell,
> is how to turn a number into a string. You do that,
> believe it or not, with the STRING command. (Do you
> see now how even simple explanations trip themselves up?)
>
> Here is an example:
>
> IDL> var_1 = 'dog'
> IDL> number = 8
> IDL> var_2 = 'something'
> IDL> mystring = var_1 + ' ' + StrTrim(number,2) + ' ' + var_2
> IDL> print, mystring
> dog 8 something
>
> If you are really lucky, you can turn numbers into strings
> with STRTRIM. If you are unlucky, you need to use the STRING
> command, with (there is a good chance of this) the FORMAT
> keyword set to a likely format.
>
> number = 3.45096754
> aString = String(number, FORMAT='(F5.2)')
>
> The program Number_Formatter is handy for this sort of thing:
>
> http://www.dfanning.com/programs/number_formatter.pro
>
> Cheers,
>
> David
>
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming:http://www.dfanning.com/
> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
I guess "simple" is a fairly relative classification. That actually
did it though. Thanks!
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| Re: Adding Text/Equations to Plots [message #65703 is a reply to message #65702] |
Mon, 16 March 2009 12:26 |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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Heather writes:
> I'm hoping someone can help me figure out a way to add equations to a
> plot. I used POLY_FIT to find the coefficients of a line for my data,
> and plotted that line. I really want to add the equation of that line
> to my plot.
>
> I thought I could use legend.pro (a routine I found at
> http://astro.uni-tuebingen.de/software/idl/astrolib/plot/leg end.pro
> that I am already calling in my routine anyhow), but that requires the
> input "items" be a string. And I couldn't figure out how to create a
> string that would call the elements of the array in which the
> coefficients are.
> (This is what I tried:
> IDL> numbers=findgen(10)
> IDL> string="This is a number: numbers(6)"
> IDL> print, string
> This is a number: numbers(6)
>
> Clearly not what I want. And I can't do something like:
> IDL> string1="This is a number: "
> IDL> print, string1, numbers(6)
> This is a number: 6.00000
>
> because what it will actually look like to the legend.pro routine is:
> IDL> string2="This is a number: " numbers(6)
>
> string2="This is a number: " numbers(6)
> ^
> % Syntax error.
>
> Any advice would be greatly appreciated, but I'm fairly new to the
> world of IDL, so please use "simple" explanations!
"Simple explanations"!? Do you see what the world is
coming to?
OK, here is a simple explanation. What you want to
do is concatenate strings. That is a big word that
means "string them together like beads on a string".
Whoops! Two different meanings of "string" here. :-(
OK, looks like you maybe know what a string is in
computer-speak. What you need to know, in a nutshell,
is how to turn a number into a string. You do that,
believe it or not, with the STRING command. (Do you
see now how even simple explanations trip themselves up?)
Here is an example:
IDL> var_1 = 'dog'
IDL> number = 8
IDL> var_2 = 'something'
IDL> mystring = var_1 + ' ' + StrTrim(number,2) + ' ' + var_2
IDL> print, mystring
dog 8 something
If you are really lucky, you can turn numbers into strings
with STRTRIM. If you are unlucky, you need to use the STRING
command, with (there is a good chance of this) the FORMAT
keyword set to a likely format.
number = 3.45096754
aString = String(number, FORMAT='(F5.2)')
The program Number_Formatter is handy for this sort of thing:
http://www.dfanning.com/programs/number_formatter.pro
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
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