JMP18: Python: jmp.Datatable: HowTo get column names without converting to pandas dataframe

[#1]

Trying to create a new column in a jmp.Datatable and check if it already exists. 

Need to get list of column names

[#2]

Hi

One sample from JSL index 

Names Default To Here( 1 );
dt = Open( "$SAMPLE_DATA/Big Class.jmp" );
n = dt << Get Column Names();
Show( n );
CNames = dt << Get Column Names( Continuous );
Show( CNames );
SNames = dt << Get Column Names( String );
Show( SNames );

[#3]

Here is the method I normally use to determine if a specific column is or is not in the data table

Names Default To Here( 1 );
dt = 
// Open Data Table: Big Class.jmp
// → Data Table( "Big Class" )
Open( "$SAMPLE_DATA/Big Class.jmp" );

If( Try( :mycolumn << get name, "" ) == "",
	New Column( "mycolumn" )
);

[#4]

Thanks for the inputs.

My bad for not mentioning that was trying to do it in the python environment

Sample code below

import jmp
import jmputils

dt = jmp.current() # get current datatable
dt.new_column('colA', jmp.DataType.Character)

Want to check if colA exists before creating a new one

[#5]

You can always fall back to jsl using jmp.run_jsl

CNames = jmp.run_jsl('''
Data Table( "Powered by Python" ) << Get Column Names( Continuous, String );
''')

Or you could maybe loop over the columns check them with col_obj.name

import jmp
dt = jmp.open(jmp.SAMPLE_DATA + "Big Class.jmp")
print(dt[0].name)

Comparing column names might not be that easy in JMP and you might want to use something like << Has Column with jmp.run_jsl (data table : message column exists(colname)? - JMP User Community)

[#6 · Accepted solution]

The data table is an iterable collection of columns.

import jmp
dt = jmp.open(jmp.SAMPLE_DATA + 'Big Class.jmp')
col_names = [ x.name for x in dt]
print(col_names)

Resulting in 

['name', 'age', 'sex', 'height', 'weight']

[#7]

From which it is a simple check to see if the name is in the list.

if 'age' in col_names:
    print('found age')