duplicate using the s_wavenames

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Mon, 12/05/2011 - 05:54 am

Hi

I'm writting a function in which I'd like to automatically duplicate the wave from a textfile. The problem is that the wave name is not always the same (it depends on some parameters used for the data acquisition) and it would be preferable for me to keep the original wavename. But I also need a unique name so that I don't have to change the wavename each time in the body function. So, I would like to duplicate the original wave called "dataX" (X varying from a textfile to another) to a wave called wave0. But the name "dataX" is not always the same, and I don't want to change it manually each time. So I think I have to use the s_wavename in the function, to automatically search the wavename and duplicate the wave dataX to wave0, but I don't know how to do it.
ps : I download the data manually, not using the loadwave function.

Thanks,

Simon
Use the $ operator.

For example:
WAVE sourceWave = $(S_wavename)


// Your actual question:
Duplicate sourceWave, wave0

// What you probably want:
Variable counter = 0
String destWaveNameString = "wave" + num2istr(counter)
Duplicate sourceWave, $(destWaveNameString)


For more information, execute the following on Igor's command line:
DisplayHelpTopic "Converting a String into a Reference Using $"

December 5, 2011 at 07:21 am - Permalink

Simon,

If s_wavename only contains the name of one wave then you can refer to it in the duplicate satement as

Duplicate $s_wavename, wave0

A quick glance at the help file for the duplicate operation indicates that you will then need to create a reference to wave0 as in

 Wave wave0

Then you can use wave0 in your code.

If s_wavename contains a list of wave names then you will have to use StringFromList to pull out individual wave names.

December 5, 2011 at 07:23 am - Permalink

Thank you, I already tried it, and it seems it only works in a macro, but not in a function. I adapt !

Simon

December 5, 2011 at 08:41 am - Permalink

Simon87 wrote:
Thank you, I already tried it, and it seems it only works in a macro, but not in a function. I adapt !

Simon


Please post your code. The $ operator works in functions as well.

December 5, 2011 at 08:47 am - Permalink

Macro dudu()
string w0
w0=stringfromlist(0, s_wavenames)
duplicate $w0, super
edit super
print w0
End

-> It works

Function dodo()
string w0, s_wavenames
w0=stringfromlist(0, s_wavenames)
duplicate $w0, super
edit super
print w0
End

-> It doesn't work (error : attempt to use a null string variable). I can't understand why.

December 5, 2011 at 09:17 am - Permalink

Simon87 wrote:

Macro dudu()
    string w0
    w0=stringfromlist(0, s_wavenames)
    duplicate $w0, super
    edit super
    print w0
End
 

-> It works

Function dodo()
    string w0, s_wavenames
    w0=stringfromlist(0, s_wavenames)
    duplicate $w0, super
    edit super
    print w0
End

-> It doesn't work (error : attempt to use a null string variable). I can't understand why.


Is that really the entire code, or an extract? Because you didn't set S_wavenames to anything in either the macro or function.

In the macro you didn't define S_wavenames, so the macro will find the global string S_wavenames.

The function won't do that unless you use:

Function dodo()
    string w0
    SVAR swn= root:s_wavenames
    w0=stringfromlist(0, swn)
    duplicate $w0, super
    edit super
    print w0
End


You can see a description of the differences between writing macros and writing functions by entering this in Igor's command line:

DisplayHelpTopic "Converting Macros To Functions"


--Jim Prouty
Software Engineer, WaveMetrics, Inc.

December 5, 2011 at 11:09 am - Permalink

If you run LoadWave from a function, it will automatically create and declare a local string variable named S_waveNames. In this case you would write:
Function Demo()
    LoadWave . . .  // Creates and declares S_waveNames
    String nameOfLoadedWave = StringFromList(0, S_waveNames)    // Get name of loaded wave
    Wave loadedWave = $nameOfLoadedWave // Create a wave reference
    Duplicate/O loadedWave, copyOfLoadedWave
End


As Jim said, if you run LoadWave from the command line, it will create a global string variable named S_waveNames. In this case you can reference it using SVAR. However, functions that depend on globals are hard to debug and maintain so this approach should be avoided.

December 5, 2011 at 02:24 pm - Permalink