Pure function with one parameter:

Pure function with two parameters:

Set to be a pure function:

Use the pure function:

Pick out named arguments from an association:

## stands for all arguments:

## n stands for arguments n and onward:

Create a pure function with attribute Listable:

#0 stands for the whole pure function:

A recursive definition for factorial using #0:

Turn a function that takes several arguments into one that takes a list of arguments:

A function that returns a function that multiplies its argument by n:

Preserve arguments in unevaluated form:

#1 uses only the first argument supplied; the rest are ignored:

Not using any arguments results in a constant pure function:

Replacements can be done inside pure functions:

Formal parameters are renamed whenever there is a possibility of confusion:

The names of the parameters do not matter:

However, reusing a name introduces a new scope:

Nested functions take their arguments one at a time:

f[#]& is the same as simply f in the univariate case:

In general, f[##]& is the same as f:

Turn a formula involving a variable into a pure function:

Use a formula in Table:

Use the corresponding pure function in an equivalent Array expression:

Special-purpose function constructs include InterpolatingFunction:

CompiledFunction:

NearestFunction:

LinearSolveFunction:

& binds more loosely than ->, so it usually needs parentheses in rules:

& binds more loosely than ?, so it usually needs parentheses in pattern tests:

Function does not evaluate its body until the function is applied:

Supplying fewer than the required number of arguments generates an error:

Define the recursion operator of recursion theory [more info]:

Use it to define the factorial function:

Newton's formula for finding a zero of a function: