I want to put symbols against the values in a column. I have different ranges for different rows.
eg. : 1st row : range is <=40 green symbol >40 and <=70 yellow symbol >70 red symbol
2nd row : range is <=20 green symbol >20 and <=50 yellow symbol >50 red symbol and so on..
Grab the Splunk 6 Dashboard Examples app and you'll find your very issue demonstrated there, along with the source code.
And in case you're using advanced xml (and can use Sideview Utils), see this.