Recode - Parse as Numbers

[#1]

Why does Recode not show a warning when a user uses the  "parse as number" option?

[#2]

What type of warning it should show?

[#3]

Something like: 
"your data table contains many rows - don't use Parse as Number in combination with any other option to update the input column!"

recode and change to numeric	64s
recode	2.8s
For each row	1.3s
recode and change to numeric -> new column	2.9s
just: change to numeric	0.06s

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Names Default To Here( 1 );
dt = New Table( "test",
	add rows( 1000000 ),
	New Column( "rw1", Character, set each value( "row " || Char( Row() ) ) ),
	New Column( "rw2", Character, set each value( "row " || Char( Row() ) ) ),
	New Column( "rw3", Character, set each value( "row " || Char( Row() ) ) ),
	New Column( "rw4", Character, set each value( "row " || Char( Row() ) ) ),
	New Column( "rw5" ),
	New Column( "rw6" )
	
);


t0 = HP Time();
dt << Begin Data Update;
dt << Recode Column( dt:rw1, {Substitute( _rcNow, "row", "" ), Num( _rcNow )}, Update Properties( 1 ), Target Column( :rw1 ) );
dt << End Data Update;
time = (HP Time() - t0) / 1000000;
Print( "recode and change to numeric" );
Show( time );


t0 = HP Time();
dt << Begin Data Update;
dt << Recode Column( dt:rw2, {Substitute( _rcNow, "row", "" )}, Update Properties( 1 ), Target Column( :rw2 ) );
dt << End Data Update;
dt:rw2 << Set Data Type( Numeric );
time = (HP Time() - t0) / 1000000;
Print( "recode" );
Show( time );

t0 = HP Time();
dt << Begin Data Update;
For Each Row( dt, dt:rw3[] = Substitute( dt:rw3, "row", "" ) );
dt << End Data Update;
dt:rw3 << Set Data Type( Numeric );
time = (HP Time() - t0) / 1000000;
Print( "For each row" );
Show( time );


t0 = HP Time();
dt << Begin Data Update;
dt << Recode Column( rw4, {Substitute( _rcNow, "row", "" ), Num( _rcNow )}, Update Properties( 1 ), Target Column( :rw5 ) );
dt << End Data Update;
time = (HP Time() - t0) / 1000000;
Print( "recode and change to numeric - new column" );
Show( time );

t0 = HP Time();
dt << Begin Data Update;
dt << Recode Column( rw6, {Num( _rcNow )}, Update Properties( 1 ), Target Column( :rw6 ) );
dt << End Data Update;
time = (HP Time() - t0) / 1000000;
Print( "just: change to numeric" );
Show( time );

[#4]

and:

Recode shows a live preview - even for table with a large numbers of rows.

Optimize your settings with a subset table and apply the resulting script to the main table.