Use a string as a condition in If- else

Question

I have a variable which is count_process = "time>=20" Now i want to use it in a IF condition like

if(time>=20){ do something }

How can I do that?

Please post a reproducible example. Perhaps you need `eval(parse(text=count_process))` — akrun, Jul 06 '15 at 12:30
if i understand you right `if(count_process =="time>=20"){ do something }` — Batanichek, Jul 06 '15 at 12:30
This feels like a place for code injection. Highly not recommended. — Vesper, Jul 06 '15 at 12:42

score 3 · Accepted Answer · answered Jul 06 '15 at 12:36

3

One option would be to extract the numeric substring with sub and use it in the if condition

 val <- as.numeric(sub('[^0-9]+', '', count_process))
 if(time >= val){do something}

Other option would be using eval(parse( (not recommended though)

 if(eval(parse(text=count_process))){do something}

answered Jul 06 '15 at 12:36

akrun

Any reason/source for chiding `eval(parse(`? – MichaelChirico Jul 06 '15 at 17:35
1

@MichaelChirico May be this [link](http://stackoverflow.com/questions/13649979/what-specifically-are-the-dangers-of-evalparse) and the links inside it helps – akrun Jul 06 '15 at 17:36

1 Answers1