How to create a custom function using VBA (Visual Basic) like in Excel

[lulunac27a]

How can I create a custom function using VBA (Visual Basic for Automation), like Microsoft Excel, which uses that language?

[anjakefala]

VisiData doesn't support VBA!

It supports Python-functions using =, and referring to column names as variables.

An example is = Units * 10 where Units is the name of a column.

[anjakefala]

Can you give me an example?

[lulunac27a]

Like converting temperatures from Celsius to Fahrenheit and vice versa.

[anjakefala]

If the function is within VisiData's scope, say by adding it to your visidatarc, you can use it as a regular Python expression.

= convert(Temperature) where convert is a function within VisiData's global scope, and Temperature is a column name.

[lulunac27a]

And another example like calculating prime numbers and Fibonacci numbers

[reagle]

And another example like calculating prime numbers and Fibonacci numbers

For fibonacci, add the function below to your .visidatarc. In a sheet, press i to create the A index column and then =fibonacci(A) will generate number for each integer in A.

cache = {0: 0, 1: 1}
def fibonacci(n):
    if n in cache:
        return cache[n]
    cache[n] = fibonacci(n - 1) + fibonacci(n - 2)
    return cache[n]

Or, if you do a lot of symbolic maths, install SymPy to the same python install you have visidata in, add import sympy to your .visidatarc and then you can call any of its functions as apt: =sympy.fibonacci(A). (sympy.ntheory has prime related functions.)