Difference between revisions of "Zip Command"
From GeoGebra Manual
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;Zip[<Expression>, <Var1>, <List1>, <Var2>, <List2>, ...] | ;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. | :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,T 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,T 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 ''list1={x^2, x^3, x^6}'' be a list of polynomials. <code>Zip[Degree[a], a, list1]</code> returns the list ''{2,3,6}''.}} | ||
{{Note|In each list the elements must be of the same type.}} | {{Note|In each list the elements must be of the same type.}} |
Revision as of 10:09, 10 July 2012
- 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,T 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.