or Part[expr, i]
gives the i part of expr.
counts from the end.
or Part[expr, i, j, ...]
is equivalent to .
gives a list of the parts , , ... of expr.
gives parts m through n.
gives parts m through n in steps of s.
- You can make an assignment like to modify any part or sequence of parts in an expression. »
- Part 0 of an expression is its head.
- Common spans of parts include:
expr[[m;;]] part m through the end expr[[;;n]] from the beginning to part n expr[[;;,j]] column j expr[[m1;;n1,m2;;n2]] submatrix
- When expr is a list, gives a list of parts. In general, the head of expr is applied to the list of parts. »
- You can get a nested list of parts from . Each part has one index from each list.
- If any of the are All or , all parts at that level are kept.
- Notice that lists are used differently in Part than in functions like Extract, MapAt, and Position.
- If expr is a SparseArray object, gives the parts in the corresponding ordinary array. »
- In StandardForm and InputForm, can be input as .
- and can be entered as Esc[[Esc and Esc]]Esc or \[LeftDoubleBracket] and \[RightDoubleBracket].
- In StandardForm, can be input as or .
Part works with expressions of any kind, not just lists: