topic Re: JSL: How to change a column to a 1-byte integer in Discussions

JSL: How to change a column to a 1-byte integer

TomF — Sat, 10 Jun 2023 23:42:38 GMT

I'm working with large files and am trying to be more thrifty when it comes to memory. I want to change the data type for some columns to "1-byte integer" using JSL but can't figure it out.

I have set my Table preferences to "Allow short numeric data format," and I can change a column's data type by hand, but I need to do it with JSL. If I change the data type by hand and then copy and paste the column into a script I see the data type for a 1-byte integer appears to be "Numeric(1)" . Maybe that is a clue.

Here are some things I've tried:

dt = open("$sample_data/big class.jmp");
dt:age << Data Type(1-byte integer);	//error "Agument to Type..."
dt:age << Data Type("1-byte integer");	//error "Agument to Type..."
dt:age << Data Type(Character);			//this works, changes to Character
dt:age << Data Type(Numeric);			//this works, changes to Numeric
dt:age << Data Type(Numeric(1));		//no error, but data type stays Numeric

It's probably something simple, but I've found no solution in the JMP Help or Community so far. Any help would be appreciated. (I'm on JMP 16.1.)

Re: JSL: How to change a column to a 1-byte integer

jthi — Thu, 13 Jan 2022 20:59:27 GMT

Search Scripting Index with "1-byte":

Seems to be working:

Re: JSL: How to change a column to a 1-byte integer

TomF — Wed, 19 Jan 2022 15:42:10 GMT

Thanks! I was hoping to find a way to tell JMP when I create the column that it's only going to be ones and zeros and therefore 1-byte integer is plenty.

It seems strange to me that I can force a column to be a 1-, 2-, or 4-byte integer using the column properties menus, but I can't do it with scripting. I wonder if this has to do with the fact that there is a preference option that allows these data types and JSL is not "smart" enough to know whether this is enabled but the GUI is.

Compressing is a solution, but I'd still be interested if anyone knows how to set modeling type before populating the column.

Re: JSL: How to change a column to a 1-byte integer

Mark_Bailey — Wed, 19 Jan 2022 17:38:22 GMT

Here is an example to make a new variable as a data column with a short word length for signed integers using a single byte.

Names Default to Here( 1 );

// open target data table
dt = Open( "$SAMPLE_DATA/Big Class.jmp" );

// set JMP preferences to accept short numeric words
Set Preference( Allow short numeric data format( 1 ) );

// create a new column using shortened numeric data type
shorty = dt << New Column( "Short Age", Numeric( 1 ), Continuous,
	Values( :age << Get As Matrix )
);

// your done. maybe set preference back to default
Set Preference( Allow short numeric data format( 0 ) );

Re: JSL: How to change a column to a 1-byte integer

pmroz — Wed, 19 Jan 2022 20:10:59 GMT

To set an existing column to 1-byte format look at this example:

// set JMP preferences to accept short numeric words
Set Preference( Allow short numeric data format( 1 ) );

dt = New Table( "Untitled",
	Add Rows( 3 ),
	New Column( "1 Byte Format",
		Numeric( 1 ),
		"Continuous",
		Set Values( [1, 2, 3] )
	),
	New Column( "New Column",
		Numeric,
		"Continuous",
		Format( "Best", 12 ),
		Set Values( [4, 5, 6] )
	)
);

dt:New Column << set data type("numeric", 1);

Re: JSL: How to change a column to a 1-byte integer

hogi — Tue, 20 May 2025 10:42:42 GMT

Please note.

N bit interger type is nice to compress the columns.

On the other hand, the user has to take care with subsequent calculations, especially when the calculation is started via the
right click / New Formula column / Formula menu:

Let's start with

dt = New Table( "numeric data",
	Add Rows( 3 ),
	New Column( "numeric 1 byte Integer",
		Numeric( 1 ),
		Set Values( [1,2,3] ),
	),
	New Column( "numeric (default)",
		Numeric,
		Set Values( [10,20,30] ),
	)	
);

and calculate

JMP copies the data type of the input column an instead of 0.1 it will return:

On the other hand, when the user selects both input column and calculates the "ratio" via:

JMP creates the column with

setting ... and the result is 0.1: