How do I create a function from an expression

[Chong_Wang]

Please see the post for intention (I am her colleague):

Generate functions inside a function from string

Well, I am working with SymPy. I would like to build a symbolic matrix and then numerically calculate it. However I found SymPy cannot do the calculation fast enough, e.g. using SymPy @vars x expr=integrate(sin(x)) f=eval(parse("x->$(repr(expr))")) g=lambdify(expr,[x]) @time subs(expr,x=>1.0) @time f(1.0) @time g(1.0) # timing: # 0.000365 seconds (80 allocations: 2.453 KiB) # 0.000003 seconds (5 allocations: 176 bytes) # 0.000016 seconds (9 allocations: 240 bytes) I found eval is the fast…

I am starting a new thread because I think eval is not the way out since it’s too restrictive to support local scope.