topic Re: JMP18: Python: jmp.Datatable: HowTo get column names without converting to pandas dataframe in Discussions

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

minion — Thu, 30 May 2024 02:57:29 GMT

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

Need to get list of column names

Re: HowTo get column names of jmp.Datatable without converting to pandas dataframe

frank_wang — Thu, 30 May 2024 01:34:10 GMT

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 );

Re: HowTo get column names of jmp.Datatable without converting to pandas dataframe

txnelson — Thu, 30 May 2024 02:28:18 GMT

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" )
);

Re: HowTo get column names of jmp.Datatable without converting to pandas dataframe

minion — Thu, 30 May 2024 02:53:46 GMT

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

Re: HowTo get column names of jmp.Datatable without converting to pandas dataframe

jthi — Thu, 30 May 2024 04:46:33 GMT

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)

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

Paul_Nelson — Thu, 30 May 2024 13:19:40 GMT

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']

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

Paul_Nelson — Thu, 30 May 2024 13:32:01 GMT

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

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