How to coerce AWK to evaluate string as math expression?

Question

Is there a way to evaluate a string as a math expression in awk?

balter@spectre3:~$ echo \"sin(0.3) 0.3\" | awk \'{print $1,sin($2)}\'
sin(0.3) 0.29552
         


        

Answer 1

awk lacks an eval(...) function. This means that you cannot do string to code translation based on input after the awk program initializes. Ok, perhaps it could be done, but not without writing your own parsing and evaluation engine in awk.

I would recommend using bc for this effort, like

[edwbuck@phoenix ~]$ echo "s(0.3)" | bc -l
.29552020666133957510

Note that this would require sin to be shortened to s as that's the bc sine operation.