how do a number sequence to unique values?

[#1]

I have the  following Column1 and need to create a new column containing the sequential number of repetitions in Column1

Column1

a

a

a

b

b

c

The resulting table should look like this:

Column1	Column2
a	1
a	2
a	3
b	1
b	2
c	1

Any suggestions how to code in in JSL? (or in column formula?) thank you!

[#2]

@rs , 

 Assuming you have a reference to the data table - let us say dt : 

dt1 = dt << Summary(
	Group( :Column 1 ),
	Freq( "None" ),
	Weight( "None" )
)

If the data is not sorted (typically it should), then you can use the sort() on the resulting table 

[#3]

thank you.  I put the code into a JMP script file (see attachment) but the script does not run.  Any suggestions? 

Would be easier to put the code in a column formula?

[#4]

Actually, I missed the part where you wanted to get a cumulative sum, rather just the sum.

I am pretty sure there is smarter and more efficient ways to do this. This will work though. 

I am essentially creating the raw data as well, for you to test and play with

// define values 
Col1Vals = {"a","a","a","a","b","b","c","c","c"}; 

dt = New Table(); 

dt << New Column("MyValues",Character,Nominal,<< Set Values(Col1Vals)); 

// Generate summary 

dt1 = dt << Summary( Group( :MyValues ), Freq( "None" ), Weight( "None" ) );

UniqueItems = dt1:MyValues << Get values; 
FrequencyOfItems = dt1 << Get As Matrix; 

Close(dt1,"No Save"); 

// Add Cumulative Frequencies back 
dt << New Column("CumulativeFreqCount",Numeric,Continuous); 
for(i = 1, i <= N Items(UniqueItems),i++,
	Rows = dt << Select Where(:MyValues == UniqueItems[i]) << Get Selected Rows; 
	ValsToAppend = Transpose(Index(1,FrequencyOfItems[i]));
	dt[Rows,"CumulativeFreqCount"] = ValsToAppend; 
	dt << Clear Select; 
   ); 

[#5 · Accepted solution]

Here is a column formula method:

// define values 
Col1Vals = {"a","a","a","a","b","b","c","c","c"}; 

dt = New Table(); 

dt << New Column("MyValues",Character,Nominal,<< Set Values(Col1Vals)); 

// Create Cumulative Frequencies
dt << New Column("CumulativeFreqCount",Numeric,Continuous); 
dt:CumulativeFreqCount << Set Each Value(
If(
	Row() == 1, 1,
	:MyValues == Lag( :MyValues, 1 ), Lag(:CumulativeFreqCount, 1 ) + 1,
	1
)); // end set each value