I don’t like Excel, but I can acknowledge that it has gotten a lot better over the last five years. One of my favourite new features is the lambda function that was added in 2021.
It lets you compose a new function from Excel’s standard library without using VBA. So, after defining ExtractFilename with lambda you can call it from a cell instead of repeating a complex formula like =RIGHT(A1,LEN(A1)-FIND("~",SUBSTITUTE(A1,"/","~",LEN(A1)-LEN(SUBSTITUTE(A1,"/",""))))). This makes sheets easier to understand and prevents a lot of common bugs.
Unfortunately, while I love the function, I have to cringe slightly every time I use it for its horrific misuse of the “lambda” name.
In the lambda calculus or any actual programming language, “lambda” signifies an anonymous function. But, in Excel, you can only use a function defined with lambda after it has been named. In other words, Excel’s lambda is only useful for defining non-lambda functions.
I try not to be too pedantic, but come on, names matter! Why would they call it lambda instead of def or function? Did they think it made them sound smart?
Admittedly, I don’t think it’s as bad as pandas.DataFrame.filter—whose documentation has to state “this routine does not filter a dataframe on its contents”—but while I’ve seen filter mocked, I haven’t been able to find anybody talking about lambda. I certainly think it is deserving of some criticism.
Microsoft’s error in naming lambda is made even worse by the fact that the let function was introduced at the same time. Between the two, let is much closer to defining a lambda function while lambda is much closer to instantiating a variable. These are my two favorite functions, but I constantly have to remind myself which one to use.
Surely, I can’t be the only one who is bothered by this?