Difference between revisions of "First Command"
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<noinclude>{{Manual Page|version=5.0}}</noinclude>{{command|cas=true|list}} | <noinclude>{{Manual Page|version=5.0}}</noinclude>{{command|cas=true|list}} | ||
| − | ;First[ | + | ;First[ <List> ] |
:Gives a new list that contains the first element of the given list. | :Gives a new list that contains the first element of the given list. | ||
:{{example|1=<div><code><nowiki>First[{1, 4, 3}]</nowiki></code> yields ''{1}''.</div>}} | :{{example|1=<div><code><nowiki>First[{1, 4, 3}]</nowiki></code> yields ''{1}''.</div>}} | ||
:{{note| 1=To get the first element use <code><nowiki>Element[{1, 4, 3}, 1]</nowiki></code>.}} | :{{note| 1=To get the first element use <code><nowiki>Element[{1, 4, 3}, 1]</nowiki></code>.}} | ||
| − | ;First[ | + | ;First[ <List>, <Number n of elements> ] |
:Gives a new list that contains just the first ''n'' elements of the given list. | :Gives a new list that contains just the first ''n'' elements of the given list. | ||
:{{example|1=<div><code><nowiki>First[{1, 4, 3}, 2]</nowiki></code> yields ''{1, 4}''.</div>}} | :{{example|1=<div><code><nowiki>First[{1, 4, 3}, 2]</nowiki></code> yields ''{1, 4}''.</div>}} | ||
| Line 18: | Line 18: | ||
:*loci generated using [[ShortestDistance Command]], [[TravelingSalesman Command]], [[Voronoi Command]], [[MinimumSpanningTree Command]], [[ConvexHull Command]] and [[Hull Command]] Commands - It returns vertices of the graph. | :*loci generated using [[ShortestDistance Command]], [[TravelingSalesman Command]], [[Voronoi Command]], [[MinimumSpanningTree Command]], [[ConvexHull Command]] and [[Hull Command]] Commands - It returns vertices of the graph. | ||
==CAS Syntax== | ==CAS Syntax== | ||
| − | ;First[ | + | ;First[ <List> ] |
:Gives a new list that contains the first element of the given list. | :Gives a new list that contains the first element of the given list. | ||
:{{example|1=<div><code><nowiki>First[{1, 4, 3}]</nowiki></code> yields ''{1}''.</div>}} | :{{example|1=<div><code><nowiki>First[{1, 4, 3}]</nowiki></code> yields ''{1}''.</div>}} | ||
:{{note| 1=To get the first element use <code><nowiki>Element[{1, 4, 3}, 1]</nowiki></code>.}} | :{{note| 1=To get the first element use <code><nowiki>Element[{1, 4, 3}, 1]</nowiki></code>.}} | ||
| − | ;First[ | + | ;First[ <List>, <Number n of elements> ] |
:Gives a new list that contains just the first ''n'' elements of the given list. | :Gives a new list that contains just the first ''n'' elements of the given list. | ||
:{{example|1=<div><code><nowiki>First[{1, 4, 3}, 2]</nowiki></code> yields ''{1, 4}''.</div>}} | :{{example|1=<div><code><nowiki>First[{1, 4, 3}, 2]</nowiki></code> yields ''{1, 4}''.</div>}} | ||
{{note| 1=<div>See also [[Last Command]].</div>}} | {{note| 1=<div>See also [[Last Command]].</div>}} | ||
Revision as of 14:14, 22 August 2015
- First[ <List> ]
- Gives a new list that contains the first element of the given list.
- Example:
First[{1, 4, 3}]yields {1}.
- Note: To get the first element use
Element[{1, 4, 3}, 1]. - First[ <List>, <Number n of elements> ]
- Gives a new list that contains just the first n elements of the given list.
- Example:
First[{1, 4, 3}, 2]yields {1, 4}.
- First[ <Text> ]
- Gives first character of the text.
- Example:
First["Hello"]yields "H".
- First[ <Text> , <Number n of elements> ]
- Gives the first n characters of the text.
- Example:
First["Hello",2]yields "He".
- First[ <Locus>, <Number n of elements> ]
- This command is useful for
- loci generated by SolveODE Command - It returns list points that were created in the first n steps of the numeric ODE-solving algorithm.
- loci generated using ShortestDistance Command, TravelingSalesman Command, Voronoi Command, MinimumSpanningTree Command, ConvexHull Command and Hull Command Commands - It returns vertices of the graph.
CAS Syntax
- First[ <List> ]
- Gives a new list that contains the first element of the given list.
- Example:
First[{1, 4, 3}]yields {1}.
- Note: To get the first element use
Element[{1, 4, 3}, 1]. - First[ <List>, <Number n of elements> ]
- Gives a new list that contains just the first n elements of the given list.
- Example:
First[{1, 4, 3}, 2]yields {1, 4}.
Note:
See also Last Command.
