Do
Do[expr, 
imax
] evaluates expr imax times.
Do[expr, 
i, imax
] evaluates expr with the variable i successively taking on the values 1 through imax (in steps of 1).
Do[expr, 
i, imin, imax
] starts with i = imin. Do[expr, 
i, imin, imax, di
] uses steps di.
Do[expr, 
i, imin, imax
, 
j, jmin, jmax
, ... ] evaluates expr looping over different values of j, etc. for each i.
Do uses the standard Mathematica TE iteration specification.
Do evaluates its arguments in a non-standard way (see Section A.4.2).
You can use Return inside Do.
Unless an explicit Return is used, the value returned by Do is Null.
See The Mathematica Book on the web: Section 1.7.3 and Section 2.5.9.
See also: For, While, Table, Nest, NestWhile, Fold.
Further Examples
