topic Re: How to replace Missing Values w/ '0' using JSL in Discussions

How to replace Missing Values w/ '0' using JSL

ambs — Mon, 28 May 2012 06:51:18 GMT

How do I replace Missing Values w/ '0' using JSL?

I can do this manually using 'Find and Replace All', but I need to incorporate it in a code that runs automatically everyday.

Re: How to replace Missing Values w/ '0' using JSL

exj — Wed, 13 Jun 2018 15:08:37 GMT

Hi,

This is based on book 'Jump into scripting'. I replace all the missing values with z.

allCols = dt2 << Get Column Names( String );
For( i = 1, i <= N Items( allCols ), i++,
/* Loop through each row. */
For( j = 1, j <= N Rows( dt2 ), j++,
/* The IsMissing function will return a ‘1’ or true if the
value is missing. If true, cell is assigned zero. */
  If( Is Missing( Column( dt2, allCols ) ),
   Column( dt2, allCols ) = "z"
  )
)
);

Hope this helps.

Re: How to replace Missing Values w/ '0' using JSL

pmroz — Tue, 29 May 2012 12:31:41 GMT

I would avoid using j as a looping variable because it is also a JSL function.

J(nrows, <ncols>, <value>)

Function: Creates a matrix of identical values.

Returns: The matrix.

Arguments:

nrows: Number of rows in matrix. If ncols is not specified, nrows is also used as ncols.

ncols: Number of columns in matrix.

value: The value used to populate the matrix. If value is not specified, 1 is used.

Re: How to replace Missing Values w/ '0' using JSL

jpkim — Wed, 13 Jun 2018 15:09:56 GMT

This is essentially the same as exj's response but a little cleaner. It does; however, only change missing in Numeric columns.

dt = current data table();
for(ij = 1, ij <= NCol(dt), ij +=1,
                CurCol = Column(dt, ij);
                If(CurCol << get data type == "Numeric",
                                For Each Row(
                                                IF(IsMissing(CurCol[]), CurCol[] = 0)
                                );
                );
);

Re: How to replace Missing Values w/ '0' using JSL

ms — Wed, 13 Jun 2018 15:07:48 GMT

Yet another way to do it but with a single loop (Numeric columns only).

dt = Current Data Table();
nc = dt << get column names( Numeric );
For( i = 1, i <= N Items( nc ), i++,
  nc[i][dt << get rows where( Is Missing( nc[i][] ) )] = 0
);

Re: How to replace Missing Values w/ '0' using JSL

ambs — Sat, 02 Jun 2012 01:55:13 GMT

thanks everone!

cheers!

Re: How to replace Missing Values w/ '0' using JSL

jkwiggins — Mon, 12 Aug 2019 12:54:16 GMT

Another way...

clsMat = dt << Get As Matrix( {"colA", "colB"} );

clsMat[Loc( Is Missing( clsMat ) )] = 0;

:colA << Set Values( clsRej[0, 1] );
:colB << Set Values( clsRej[0, 2] );

etc.

logical indexing is often faster than loops

Re: How to replace Missing Values w/ '0' using JSL

masakit — Thu, 14 Jul 2016 21:04:28 GMT

cool! ... in the last 2 lines, clsRej should be replaced to clsMat, right?

meanwhile, do we have any similar solutions for character column?

Re: How to replace Missing Values w/ '0' using JSL

msharp — Mon, 12 Aug 2019 12:55:15 GMT

Since no one else answered, the solution is the same, just grab character columns instead and set the rows equal to the character you find fitting--"N/A" in the below case.

Just be careful, setting it =0 will change the column to numeric and will remove all the character data, however ="0" should be fine.

dt = Current Data Table();
nc = dt << get column names( Character );

For( i = 1, i <= N Items( nc ), i++,
  nc[i][dt << get rows where( Is Missing( nc[i][] ) )] = "N/A"
);

Re: How to replace Missing Values w/ '0' using JSL

Kevin_Anderson — Fri, 22 Jul 2016 22:08:43 GMT

Sorry to be late to this party, but I feel compelled to interject: Setting missing values to zero (or the mean or any other single imputation method) has serious drawbacks. Most of these approaches produce biased parameter estimates, even in ideal conditions where the data are Missing Completely At Random. There are much better ways to deal with missing data.

Re: How to replace Missing Values w/ '0' using JSL

msharp — Fri, 22 Jul 2016 22:25:42 GMT

While what you say is true, it makes assumptions about the data. For example, maybe his data isn't continuous? Sometimes 0 isn't recorded and instead left as missing. If someone were to try and do a Oneway analysis using 0 as false and 1 as true they'd have a problem if their zero's ended up displaying as missing, since Oneway analysis ignores missing rows in JMP. They'd end up with ONLY ONE category!

There are other reasons 0 could show up as missing. Usually storing 0 in a large database is a waste of space. Since Pokemon Go is big right now, I'll use it as an example. I might want to record all the pokemon I caught in a day, 12 ratattas and 6 pidgeys. I wouldn't however, want to then store 0 for the other 148 pokemon I didn't catch that day. If I did I'd quickly fill up my database with useless information. Thus, if I queried my data I'd get missing for most of my pokemon at any given time, but missing is = to 0.

In similar situations you could get missing data that are equivalent to 0 b/c of data conversion issues, poorly designed queries, ect.

Re: How to replace Missing Values w/ '0' using JSL

Kevin_Anderson — Fri, 22 Jul 2016 22:37:34 GMT

That's all true. I felt like it was time to put up a Caution flag. Just because we can do something in JMP doesn't always mean we should.

Re: How to replace Missing Values w/ '0' using JSL

msharp — Fri, 22 Jul 2016 23:13:50 GMT

Absolutely, I appreciate the word of caution. I for sure, didn't think about it.

It's also important to remember that missing data can be valuable data, and sometimes it's best to leave it as is!

Re: How to replace Missing Values w/ '0' using JSL

RaginCajun — Mon, 12 Aug 2019 12:52:01 GMT

This works when I am running it from a scripting window using play button, but not within a debugger or launching it by autorun of the .jsl.

dtLongestWaitStates << set name( "LongestWaitStates" );
dtLongestWaitStates = Current Data Table();
nc = dtLongestWaitStates << get column names( numeric );
For( i = 1, i <= N Items( nc ), i++,
	nc[i][dtLongestWaitStates << get rows where( Is Missing( nc[i][] ) )] = 0
);

RaginCajun

JMP13.2.1