casa6

​

import argparse

import os

import traceback

from casatools import table

############################################################

##

##

## TAQL Documentation:

## https://casacore.github.io/casacore-notes/199.html

## https://casa.nrao.edu/docs/CasaRef/table.taql.html

## https://casa.nrao.edu/aips2_docs/notes/199/node3.html

##

##

############################################################

​

def set_taql_query(itable, otable = None, lrows='2', overwrite = False):

    '''Select the limit of rows to keep from an input table and copy them to an output table'''

​

    if otable is None:

        otable = os.path.basename(itable) + '_OUT'

​

    tb=table()

    # TaQL query command 

    selq="SELECT from "+itable+" LIMIT "+ str(lrows)

    #selq="SELECT from "+msfile+" WHERE FLAG_ROW==TRUE && NOT ALL(FLAG)==TRUE LIMIT 10"

    # Open the table

    try:

        tb.open(itable, nomodify=True)

        print('Running TaQL selection on {}'.format(itable))

        print('Original table has {} rows'.format(tb.nrows()))

        # Query the table. It returns an instance of the tb tool

        seltbl = tb.taql(selq)

        nrow = seltbl.nrows()

        print('Selection has {} rows'.format(nrow))

        if (nrow > 0):

            if os.path.exists(otable) and overwrite == False:

                print('ERROR: Output table {} already exist. Will not overwrite it'.format(otable))

                return

                #os.system('rm -rf '+outtable)

            print('Saving selection to {}'.format(otable))

            out = seltbl.copy(otable,deep=True,valuecopy=True)

            out.close() 

        else:

            print('ERROR: {} has {} rows. Will not write to {}'.format(itable,nrow, otable))

            return

    #        seltbl.flush()

    finally:

        tb.close()

        seltbl.close()

        del seltbl

​

if __name__ == "__main__":

    parser = argparse.ArgumentParser()

    parser.add_argument("-i", "--input", help='name of input table to read select from', required=True)

    parser.add_argument("-o", "--output",help='name of output table to create', required=False)