The evstr() Function in Scilab

In Scilab, the function evstr() aptly stands for "evaluate string". Its primary role is to transform a string into its corresponding numerical representation.

evstr(x)

When calling evstr(x), x represents the string you wish to evaluate.

Importantly, this string can either be a plain number or encapsulate a more complex mathematical expression.

One of the key benefits of the evstr() function is its ability to seamlessly convert a string that embodies a mathematical formulation into a precise numerical value or another data type.

Consider this straightforward example.

Suppose you assign the string "10" to the variable x

x="10"

By invoking the evstr() function, the string is readily converted to its numerical counterpart.

evstr(x)

The output? A clear-cut integer: 10.

ans=
10

Expanding its capabilities, evstr() can also interpret strings infused with mathematical constructs.

Take for instance:

x = "3 + 4"

On deploying the evstr() function on this string

evstr(x)

Scilab adeptly processes the string, discerning it as the mathematical sequence 3+4, and subsequently yielding the result:

ans=
7.

But there's more. Evstr() is versatile enough to evaluate strings enveloping mathematical functions. An example to illustrate this.

Given the string "sqrt(16)", the function's invocation looks like:

evstr("sqrt(16)")

Here, Scilab astutely identifies and computes the sqrt(16) function, delivering the square root of 16, or 4.

ans=
4.

Notably, the prowess of evstr() isn't just restricted to numbers and functions. It can discern strings referencing variable names as well.

Let's assign a value of 2 to the variable "a".

a=2

On evaluating the string "a+1" with evstr()

evstr("a+1")

The function astutely recognizes "a" as a variable, retrieves its value (2 in this case), and performs the calculation 2+1, rendering the result as:

ans=
3.

While the evstr() function is undeniably potent, it's imperative to approach it with prudence, especially when sourcing strings externally.

Always prioritize verifying the integrity and intent of the string before its evaluation.