Hash[expr] gives an integer hash code for the expression expr.Hash[expr, " type"] gives an integer hash code of the specified type for expr.

$LibraryError returns the system-dependent error message from loading a library, or None if there was no error.

When you do calculations with arbitrary-precision numbers, Mathematica keeps track of precision at all points. In general, Mathematica tries to give you results which have ...

Sparse representations of matrices are useful because they do not store every element. If one particular value appears very frequently it can be very advantageous to use a ...

The syntax of the Mathematica language is unique among modern languages in allowing not just ordinary ASCII characters, but also a variety of special characters that greatly ...

The replacement operator /. allows you to apply transformation rules to a specific expression. Often, however, you want to have transformation rules automatically applied ...

Unicode: F4A2 Alias: Esc xnor Esc. Infix operator with built-in evaluation rules. x  y is by default interpreted as Xnor[x,y].

SameTest is an option whose setting gives a pairwise comparison function to determine whether expressions should be considered the same.

Unicode: 2262. Alias: Esc !=== Esc. Infix similarity operator. x ≢ y is by default interpreted as NotCongruent[x,y].

Unicode: 2209. Aliases: Esc !el Esc, Esc  !elem Esc. Infix set relation operator with built-in evaluation rules. x ∉ y is by default interpreted as NotElement[x,y].