clone a column

[#1]

Hi All,

I want to clone a column in the data table (make a new identical column in all but it’s name). Is there a more sleek (and robust) way of doing this or do I need to extract the values and all properties and assign them to the new column as such:

dt3 = Open( "$SAMPLE_DATA/Cars.jmp" );

// add a column property

dt3:Make << Set Property(

          "Value Colors",

          {"Acura" = -13977687, "Audi" = -3780931, "BMW" = -4222943, "Buick" = -

          13596966, "Cadillac" = -2211217, "Chevrolet" = -10562780, "Chrysler" = -

          13156647, "Daihatsu" = -2078390, "Dodge" = -13182413, "Eagle" = -9549600,

          "Ford" = -2334147, "Geo" = -13772446, "Honda" = -9282864, "Hyundai" = -

          6995852, "Infiniti" = -1524612, "Isuzu" = -9458080, "Jeep" = -14452073,

          "Lexus" = -6391856, "Lincoln" = -2745505, "Mazda" = -10199751, "Mercedes" =

          -7150697, "Mercury" = -10513726, "Mitsubishi" = -8381519, "Nissan" = -

          3502441, "Oldsmobile" = -3615440, "Peugeot" = -13925307, "Plymouth" = -

          11502354, "Pontiac" = -7449196, "Renault" = -9229791, "Saab" = -4074344,

          "Saturn" = -13050224, "Subaru" = -12565885, "Suzuki" = -2068529, "Toyota" =

          -4494272, "Volkswagen" = -11824110, "Volvo" = -8734293, "Yugo" = -13849421}

     ) << color cell by value;

// clone the column

clone_column = dt3:Make << Get script;

clone_column;

[#2]

That looks very sleek to me. Have you experienced any problems with robustness?

If you do not want to waste memory on a variable it can be simplified into a oneliner:

Eval(dt3:Make << Get script) << set name("Clone");

For cloning multiple columns , I would consider making a subset of these, rename the columns and update with the original data table.

[#3]

Thanks MS​,

i am surprised there is no jsl command for duplicating an existing column. in addition, if dt3 is not the active table it creates the new column in an other table.

[#4]

You can make it more robust by editing the script variable prior to evaluation i.e. prepend "dt << " to the expression.

[#5 · Accepted solution]

Here is a completed example of one way to prepend the data table pointer:

Eval(Parse("(dtxxx<<"||char(dt3:Make << Get script)||") << set name(\!"Clone\!");"));

[#6 · Accepted solution]

thanks Dave@Pega-Analytics txnelson​,

this is what i was looking for. i didn't expect duplicating a column to be so cumbersome.

the following is my final script:

Names Default To Here( 1 );

dt3 = Open( "$SAMPLE_DATA/Cars.jmp" , private);

// clone into the same table

Eval(Parse("(dt3<<"||char(dt3:Make << Get script)||") << set name(\!"Clone\!");"));

// proof that the column was cloned - check log

dt3:Clone << get script;

close (dt3, no save);

best,

ron

[#7 · Accepted solution]

I'm really not sure what value there is in keeping column properties like value colors in a private table.  If the data is all you care about (typically true for private tables), the simpler method below could be used.:

dt3 << New Column("Make Clone", Formula(dt3:Make))

[#8]

Thanks MS​,

It is true that colors are not very useful in a private table.

the thing is that I am writing an algorithm based on a heuristic process. this means that I need to have a script that would do what i would if i had to "read" the data lines one by one my self and interpret it (here is where i need the colors). on the other hand the script needs to be fast when running so i need to bounce back and fourth between tables I see and fast running ones (private). this transition between visual and private tables introduces robustness challenges while scripting across a few open tables.

ron

[#9]

the robustness issue came when using private tables since the clone was sent to another table which was not private.

[#10]

Hi MS, Would you mind explaining how this command clones the selected column in a dt? Eval(dt3:Make << Get script) << set name("Clone"); I realize this is not normally the kind of question asked here and it was 5 years ago but this is the most opaque command I have seen in any programming language I have used. I works great however!