[R] controlling the number of times a script is repeated in a loop

[hadley wickham]

On Sun, Nov 30, 2008 at 12:21 PM, Salas, Andria Kay <aks2515 at uncw.edu> wrote:
> I am running a large for loop and at the end of each iteration a matrix is produced.  The program changes the columns in the matrix, and each time a column is added the name of that column is "y".  All original columns have no column name.  Due to the nature of the program, all original columns will eventually be replaced with new columns each with the column name "y". It is at this point that I want the program to stop running the for loop (right now I just have it running for 20 iterations resulting in a matrix with a mix of old and new columns).  I was thinking maybe I could do something with an if else statement and the command colnames.  For example:
>
> If(colnames all are "y") (stop) else (run the program again)

Have a look at ?"while" :

while(!(colnames all are "y")) { run the program again }

Hadley

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