topic adding prefix to Character column values in an efficient way in Discussions

adding prefix to Character column values in an efficient way

newbie_alex — Wed, 08 Nov 2017 11:36:00 GMT

Hello,

I have a character column with an unknown number of different values.

I would like to add a string prefix to each value but I struggle with doing so in an efficient way without creating a new column and without a for loop because it is slow.

Example for a single value:

Value is "12"

new value should be "PREFIX 12"

Is there a way to do this with JMP 12?

Here is the code without the step to add the prefix:

Names Default to Here( 1 );
dt = Open( "$SAMPLE_DATA/Big Class.jmp" );
dt:Age << Data Type( Character );
// Get the values of age into a vector
ageVals = dt:Age << getValues;
// do not know what to do here. would like to add a PREFIX without a for loop (which would be slow)
???
// Put the new values back into the column
dt:Age << setValues(ageVals);

Best regards,

Alex

Re: adding prefix to Character column values in an efficient way

txnelson — Wed, 08 Nov 2017 11:50:38 GMT

I believe the quickest way to do this would be

Names Default to Here( 1 );
dt = Open( "$SAMPLE_DATA/Big Class.jmp" );
dt:Age << Data Type( Character );
for each row(
	dt:Age = "PREFIX " || dt:Age
);

Re: adding prefix to Character column values in an efficient way

newbie_alex — Wed, 08 Nov 2017 12:33:34 GMT

Thank you.

That is actually quicker than expected even for my big data set.

Would you please help me understand why this is quicker than a regular for loop?

Re: adding prefix to Character column values in an efficient way

txnelson — Wed, 08 Nov 2017 14:40:19 GMT

I suspect the reason this is faster, is because it is a function that has very specific actions, and therefore has been optimized.