| Looping through structures [message #92799] |
Tue, 01 March 2016 09:53  |
wdolan
Messages: 29
Registered: June 2015
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Junior Member |
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So I am analyzing a years worth of data, which I got in the form of structures for each month.
For example
StrucJan has arrays (is tags the correct word?) called, lon, lat, gas_conc (we are measuring gas concentration). And StrucFeb also has the tags lon, lat, and gas_conc. Each month is in the same format.
I've got a bunch of code that does calculations with the January data. But I'm not sure how to loop over it so it does all the same calculations with the February data, and then the march, april, may etc. data (all of which are in the same format with the exact same tags).
Hopefully this makes sense!
Any ideas?
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| Re: Looping through structures [message #92800 is a reply to message #92799] |
Tue, 01 March 2016 10:16  |
Paul Van Delst[1]
Messages: 1157
Registered: April 2002
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Senior Member |
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Hello,
On 03/01/16 12:53, Wayana Dolan wrote:
> So I am analyzing a years worth of data, which I got in the form of
> structures for each month.
>
> For example
>
> StrucJan has arrays (is tags the correct word?) called, lon, lat,
> gas_conc (we are measuring gas concentration). And StrucFeb also has
> the tags lon, lat, and gas_conc. Each month is in the same format.
>
> I've got a bunch of code that does calculations with the January
> data. But I'm not sure how to loop over it so it does all the same
> calculations with the February data, and then the march, april, may
> etc. data (all of which are in the same format with the exact same
> tags).
>
> Hopefully this makes sense!
Some methods are below...(not sure anonymous structures are required or not)
IDL> structjan={lat:1.0, lon:2.0, gas_conc:380.0}
IDL> structfeb={lat:3.0, lon:4.0, gas_conc:394.0}
IDL> structmar={lat:5.0, lon:6.0, gas_conc:403.0}
* Array
IDL> structyear = [structjan, structfeb, structmar]
IDL> help, structyear
STRUCTYEAR STRUCT = -> <Anonymous> Array[3]
IDL> help, structyear[2].gas_conc
<Expression> FLOAT = 403.000
* Hash
IDL> structyear=hash()
IDL> structyear['jan']=structjan
IDL> structyear['feb']=structfeb
IDL> structyear['mar']=structmar
IDL> help, structyear['mar'].gas_conc
<Expression> FLOAT = 403.000
* List
IDL> structyear=list()
IDL> structyear.add, structjan
IDL> structyear.add, structfeb
IDL> structyear.add, structmar
IDL> help, structyear[2].gas_conc
<Expression> FLOAT = 403.000
The usefulness of these to you depends mostly (I think) on how your
processing code cycles through the months. E.g. array and year assume
jan-dec is 0-11. Hash assumes a key (doesn't have to be a month string,
can be an integer number too.)
cheers,
paulv
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