str(x1[,x2[,x3,…]])

Takes any number of arguments of any type, variables, or constants, converts any numerics to strings, and concatenates all inputs into a single output string. If any argument is a date/time variable or constant, it is treated as the double-precision number that is its internal representation. All numbers other than integers are written with 6 decimals (for more control, use $fmt or $dtwrite). The output is a string variable.