I'm new to GIS in general and field calculator in particular. 

I have a basic attribute table with three columns. I'd like to assign values to column C based on what is in column A. If Column A = 8 then I need column C to read "pine forest". Column C is set for text with length=100 so that should not be a problem. 

I had thought I could do this by selecting all of the records where column A = 8 and then using field calculator in column C to assign them the label "pine forest". However this results in an error message saying that the calculated value is invalid because it is either too large or because it is a string, which are both wrong. 


Question: Intersection of lists of disjoint intervals
Answer: intervalsA = {{1, 2}, {3, 4}, {5, 7}, {8, 8.5}};
intervalsB = {{1.5, 3.5}, {4.1, 6}, {9, 10}};
IntervalIntersection @@ Interval @@@ {intervalsA, intervalsB}



  Interval[{1.5, 2}, {3, 3.5}, {5, 6}]