# Difference between revisions of "KeepIf Command"

From GeoGebra Manual

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:{{note|1=For list of numbers arbitrary condition may be used. For list of other objects one can use only conditions of the form <code>x==constant</code> or <code>x!=constant</code>.}} | :{{note|1=For list of numbers arbitrary condition may be used. For list of other objects one can use only conditions of the form <code>x==constant</code> or <code>x!=constant</code>.}} | ||

− | + | ; KeepIf[ <Condition>, <Variable>, <List> ] | |

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: This syntax allows a more flexible condition, eg for Points ''P, Q, R'' <code>KeepIf[x(A) < 3, A, {P, Q, R}]</code> will filter the points whose ''x''-coordinate is greater than 3 out of the list. The Variable A is replaced in turn with ''P'' then ''Q'' then ''R'' for the check. | : This syntax allows a more flexible condition, eg for Points ''P, Q, R'' <code>KeepIf[x(A) < 3, A, {P, Q, R}]</code> will filter the points whose ''x''-coordinate is greater than 3 out of the list. The Variable A is replaced in turn with ''P'' then ''Q'' then ''R'' for the check. | ||

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## Revision as of 22:53, 5 January 2013

- KeepIf[ <Condition>, <List> ]
- Creates a new list that only contains those elements of the initial list that fulfil the condition.
**Example:**`KeepIf[x<3, {1, 2, 3, 4, 1, 5, 6}]`

returns the new list*{1, 2, 1}*.

**Note:**For list of numbers arbitrary condition may be used. For list of other objects one can use only conditions of the form`x==constant`

or`x!=constant`

.

- KeepIf[ <Condition>, <Variable>, <List> ]
- This syntax allows a more flexible condition, eg for Points
*P, Q, R*`KeepIf[x(A) < 3, A, {P, Q, R}]`

will filter the points whose*x*-coordinate is greater than 3 out of the list. The Variable A is replaced in turn with*P*then*Q*then*R*for the check.