Difference between revisions of "Zip Command"
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;Zip[ <Expression>, <Var1>, <List1>, <Var2>, <List2>, ...]:Creates [[Lists|list]] of objects obtained by substitution of variables in the expression by elements of corresponding lists. Length of the resulting list is minimum of lengths of input lists. | ;Zip[ <Expression>, <Var1>, <List1>, <Var2>, <List2>, ...]:Creates [[Lists|list]] of objects obtained by substitution of variables in the expression by elements of corresponding lists. Length of the resulting list is minimum of lengths of input lists. | ||
:{{example|1=Let P, Q, R, S be some points. <code>Zip[Midpoint[A, B], A, {P, Q}, B, {R, S}]</code> returns a list containing [[Midpoint Command|midpoints]] of segments ''PR'' and ''QS''.}} | :{{example|1=Let P, Q, R, S be some points. <code>Zip[Midpoint[A, B], A, {P, Q}, B, {R, S}]</code> returns a list containing [[Midpoint Command|midpoints]] of segments ''PR'' and ''QS''.}} | ||
Revision as of 09:39, 12 August 2015
- Zip[ <Expression>, <Var1>, <List1>, <Var2>, <List2>, ...]
- Creates list of objects obtained by substitution of variables in the expression by elements of corresponding lists. Length of the resulting list is minimum of lengths of input lists.
- Example: Let P, Q, R, S be some points.
Zip[Midpoint[A, B], A, {P, Q}, B, {R, S}]returns a list containing midpoints of segments PR and QS.
- Example: Let list1={x^2, x^3, x^6} be a list of polynomials.
Zip[Degree[a], a, list1]returns the list {2, 3, 6}.
Note: In each list the elements must be of the same type.
Comments
It's actually enough to provide a single list to Zip(). This makes it a shorter alternative to Sequence() when all you want is to traverse a list. For example, Zip(a^2, a, listOfNumbers) is much shorter than Sequence(Element(listOfNumbers, a)^2, a, 1, Length(listOfNumbers)) (albeit in this case it's easier to just do listOfNumbers^2.)
Hint: Zip() is similar to a construct known as "map" in other programming languages.
