StringReplaceList["string", s -> sp] or StringReplaceList["string", {s_1 -> sp_1, s_2 -> sp_2, ...}] gives a list of the strings obtained by replacing each individual ...

Tr[list] finds the trace of the matrix or tensor list. Tr[list, f] finds a generalized trace, combining terms with f instead of Plus. Tr[list, f, n] goes down to level n in ...

UnitBox[x] represents the unit box function, equal to 1 for |x| <= 1/2 and 0 otherwise.UnitBox[x_1, x_2, ...] represents the multidimensional unit box function, equal to 1 if ...

UnitTriangle[x] represents the unit triangle function on the interval |x| <= 1 .UnitTriangle[x_1, x_2, ...] represents the multidimensional unit triangle function on the ...

Which[test_1, value_1, test_2, value_2, ...] evaluates each of the test_i in turn, returning the value of the value_i corresponding to the first one that yields True.

Now that we have introduced the basic features of patterns in Mathematica, we can use them to give a more or less complete example. We will show how you could define your own ...

Converting notebooks to HTML. Export has many options applying to HTML export that allow you to specify how notebooks should be converted for web browsers with different ...

Mathematica usually pays no attention to whether variables like x stand for real or complex numbers. Sometimes, however, you may want to make transformations which are ...

Finding elements that match a pattern. This gives the elements of the list which match the pattern x^_. Here is the total number of elements which match the pattern.

In doing many kinds of calculations, you need to evaluate expressions when variables take on particular values. In many cases, you can do this simply by applying ...