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>position, position-if, position-if-not | Common Lisp Nova Spec</TITLE
><META CHARSET="US-ASCII"
><LINK REL="canonical" HREF="f_position.html"
><LINK REL="next" HREF="f_search.html" TYPE="text/html" TITLE="search"
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><DIV CLASS="breadcrumb"
><SPAN CLASS="breadcrumb-item"
><A HREF="index.html"
>Common Lisp Nova Spec</A
></SPAN
> <SPAN CLASS="breadcrumb-item"
>&#8594; <A HREF="17_Sequences.html"
>17. Sequences</A
></SPAN
> <SPAN CLASS="breadcrumb-item"
>&#8594; <A HREF="17_3_Sequences_Dictionary.html"
>17.3 Sequences Dictionary</A
></SPAN
> <SPAN CLASS="breadcrumb-item"
>&#8594; <A HREF="f_position.html"
>position, position-if, position-if-not</A
></SPAN
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><HR
><TABLE WIDTH="100%" CELLSPACING="0" CELLPADDING="0"
><TR
><TD ALIGN="LEFT" VALIGN="BASELINE" WIDTH="100%" CLASS="name"
><SPAN CLASS="idx" DATA-KIND="idxref" DATA-TERM="position, position-if, position-if-not"
></SPAN
><B
>position, position-if, position-if-not</B
></TD
><TD ALIGN="RIGHT" VALIGN="BASELINE" WIDTH="0" NOWRAP="NOWRAP" CLASS="ftype"
><I
>Function</I
></TD
></TR
></TABLE
><HR
></DIV
><UL CLASS="subtoc"
></UL
><DL
><DT
><B
>Syntax</B
></DT
><DD
><P CLASS="j"
><B
>position</B
> <SPAN CLASS="cmssi"
>item</SPAN
> <SPAN CLASS="cmssi"
>sequence</SPAN
> <SPAN CLASS="cmtt"
>&amp;key</SPAN
> <SPAN CLASS="cmssi"
>from-end</SPAN
> <SPAN CLASS="cmssi"
>test</SPAN
> <SPAN CLASS="cmssi"
>test-not</SPAN
> <SPAN CLASS="cmssi"
>start</SPAN
> <SPAN CLASS="cmssi"
>end</SPAN
> <SPAN CLASS="cmssi"
>key</SPAN
> <SPAN CLASS="arrow"
>&#8594;</SPAN
> <SPAN CLASS="cmssi"
>position</SPAN
></P
><P CLASS="j"
><B
>position-if</B
> <SPAN CLASS="cmssi"
>predicate</SPAN
> <SPAN CLASS="cmssi"
>sequence</SPAN
> <SPAN CLASS="cmtt"
>&amp;key</SPAN
> <SPAN CLASS="cmssi"
>from-end</SPAN
> <SPAN CLASS="cmssi"
>start</SPAN
> <SPAN CLASS="cmssi"
>end</SPAN
> <SPAN CLASS="cmssi"
>key</SPAN
> <SPAN CLASS="arrow"
>&#8594;</SPAN
> <SPAN CLASS="cmssi"
>position</SPAN
></P
><P CLASS="j"
><B
>position-if-not</B
> <SPAN CLASS="cmssi"
>predicate</SPAN
> <SPAN CLASS="cmssi"
>sequence</SPAN
> <SPAN CLASS="cmtt"
>&amp;key</SPAN
> <SPAN CLASS="cmssi"
>from-end</SPAN
> <SPAN CLASS="cmssi"
>start</SPAN
> <SPAN CLASS="cmssi"
>end</SPAN
> <SPAN CLASS="cmssi"
>key</SPAN
> <SPAN CLASS="arrow"
>&#8594;</SPAN
> <SPAN CLASS="cmssi"
>position</SPAN
></P
></DD
><DT
><B
>Arguments and Values</B
></DT
><DD
><P CLASS="j"
><VAR CLASS="param"
>item</VAR
> &#8212; an <A HREF="26_1_Glossary.html#object"
><EM CLASS="term"
>object</EM
></A
>. </P
><P CLASS="j"
><VAR CLASS="param"
>sequence</VAR
> &#8212; a <A HREF="26_1_Glossary.html#proper_sequence"
><EM CLASS="term"
>proper sequence</EM
></A
>. </P
><P CLASS="j"
><VAR CLASS="param"
>predicate</VAR
> &#8212; a <A HREF="26_1_Glossary.html#designator"
><EM CLASS="term"
>designator</EM
></A
> for a <A HREF="26_1_Glossary.html#function"
><EM CLASS="term"
>function</EM
></A
> of one argument that returns a <A HREF="26_1_Glossary.html#generalized_boolean"
><EM CLASS="term"
>generalized boolean</EM
></A
>. </P
><P CLASS="j"
><VAR CLASS="param"
>from-end</VAR
> &#8212; a <A HREF="26_1_Glossary.html#generalized_boolean"
><EM CLASS="term"
>generalized boolean</EM
></A
>. The default is <A HREF="26_1_Glossary.html#false"
><EM CLASS="term"
>false</EM
></A
>. </P
><P CLASS="j"
><VAR CLASS="param"
>test</VAR
> &#8212; a <A HREF="26_1_Glossary.html#designator"
><EM CLASS="term"
>designator</EM
></A
> for a <A HREF="26_1_Glossary.html#function"
><EM CLASS="term"
>function</EM
></A
> of two <A HREF="26_1_Glossary.html#argument"
><EM CLASS="term"
>arguments</EM
></A
> that returns a <A HREF="26_1_Glossary.html#generalized_boolean"
><EM CLASS="term"
>generalized boolean</EM
></A
>. </P
><P CLASS="j"
><VAR CLASS="param"
>test-not</VAR
> &#8212; a <A HREF="26_1_Glossary.html#designator"
><EM CLASS="term"
>designator</EM
></A
> for a <A HREF="26_1_Glossary.html#function"
><EM CLASS="term"
>function</EM
></A
> of two <A HREF="26_1_Glossary.html#argument"
><EM CLASS="term"
>arguments</EM
></A
> that returns a <A HREF="26_1_Glossary.html#generalized_boolean"
><EM CLASS="term"
>generalized boolean</EM
></A
>. </P
><P CLASS="j"
><VAR CLASS="param"
>start</VAR
>, <VAR CLASS="param"
>end</VAR
> &#8212; <A HREF="26_1_Glossary.html#bounding_index_designator"
><EM CLASS="term"
>bounding index designators</EM
></A
> of <VAR CLASS="param"
>sequence</VAR
>. The defaults for <VAR CLASS="param"
>start</VAR
> and <VAR CLASS="param"
>end</VAR
> are <CODE CLASS="f"
>0</CODE
> and <SPAN CLASS="misc"
><B
>nil</B
></SPAN
>, respectively. </P
><P CLASS="j"
><VAR CLASS="param"
>key</VAR
> &#8212; a <A HREF="26_1_Glossary.html#designator"
><EM CLASS="term"
>designator</EM
></A
> for a <A HREF="26_1_Glossary.html#function"
><EM CLASS="term"
>function</EM
></A
> of one argument, or <SPAN CLASS="misc"
><B
>nil</B
></SPAN
>. </P
><P CLASS="j"
><VAR CLASS="param"
>position</VAR
> &#8212; a <A HREF="26_1_Glossary.html#bounding_index"
><EM CLASS="term"
>bounding index</EM
></A
> of <VAR CLASS="param"
>sequence</VAR
>, or <SPAN CLASS="misc"
><B
>nil</B
></SPAN
>.</P
></DD
><DT
><B
>Description</B
></DT
><DD
><P CLASS="j"
><A HREF="f_position.html" CLASS="funref"
><B
>position</B
></A
>, <A HREF="f_position.html" CLASS="funref"
><B
>position-if</B
></A
>, and <A HREF="f_position.html" CLASS="funref"
><B
>position-if-not</B
></A
> each search <VAR CLASS="param"
>sequence</VAR
> for an <A HREF="26_1_Glossary.html#element"
><EM CLASS="term"
>element</EM
></A
> that <EM CLASS="term"
>satisfies the test</EM
>. </P
><P CLASS="j"
>The <VAR CLASS="param"
>position</VAR
> returned is the index within <VAR CLASS="param"
>sequence</VAR
> of the leftmost (if <VAR CLASS="param"
>from-end</VAR
> is <A HREF="26_1_Glossary.html#true"
><EM CLASS="term"
>true</EM
></A
>) or of the rightmost (if <VAR CLASS="param"
>from-end</VAR
> is <A HREF="26_1_Glossary.html#false"
><EM CLASS="term"
>false</EM
></A
>) <A HREF="26_1_Glossary.html#element"
><EM CLASS="term"
>element</EM
></A
> that <EM CLASS="term"
>satisfies the test</EM
>; otherwise <SPAN CLASS="misc"
><B
>nil</B
></SPAN
> is returned. The index returned is relative to the left-hand end of the entire <VAR CLASS="param"
>sequence</VAR
>, regardless of the value of <EM CLASS="term"
>start</EM
>, <EM CLASS="term"
>end</EM
>, or <EM CLASS="term"
>from-end</EM
>.</P
></DD
><DT
><B
>Examples</B
></DT
><DD
><PRE CLASS="screen"
>(position #\a "baobab" :from-end t) <SPAN CLASS="cmsy"
><SPAN CLASS="arrow"
>&#8594;</SPAN
></SPAN
> 4
(position-if #'oddp '((1) (2) (3) (4)) :start 1 :key #'car) <SPAN CLASS="cmsy"
><SPAN CLASS="arrow"
>&#8594;</SPAN
></SPAN
> 2
(position 595 '()) <SPAN CLASS="cmsy"
><SPAN CLASS="arrow"
>&#8594;</SPAN
></SPAN
> NIL
(position-if-not #'integerp '(1 2 3 4 5.0)) <SPAN CLASS="cmsy"
><SPAN CLASS="arrow"
>&#8594;</SPAN
></SPAN
> 4</PRE
></DD
><DT
><B
>Exceptional Situations</B
></DT
><DD
><P CLASS="j"
>Should be prepared to signal an error of <A HREF="26_1_Glossary.html#type"
><EM CLASS="term"
>type</EM
></A
> <A HREF="t_type-error.html" CLASS="typeref"
><B
>type-error</B
></A
> if <VAR CLASS="param"
>sequence</VAR
> is not a <A HREF="26_1_Glossary.html#proper_sequence"
><EM CLASS="term"
>proper sequence</EM
></A
>.</P
></DD
><DT
><B
>See Also</B
></DT
><DD
><P CLASS="j"
><A HREF="f_find.html" CLASS="funref"
><B
>find</B
></A
>, <A HREF="3_6_Traversal_Rules_and_Side_Effects.html#sec_3_6" CLASS="secref"
><SPAN CLASS="cmr"
>Section</SPAN
> <SPAN CLASS="cmr"
>3.6</SPAN
> <SPAN CLASS="cmr"
>(Traversal</SPAN
> <SPAN CLASS="cmr"
>Rules</SPAN
> <SPAN CLASS="cmr"
>and</SPAN
> <SPAN CLASS="cmr"
>Side</SPAN
> <SPAN CLASS="cmr"
>Effects)</SPAN
></A
></P
></DD
><DT
><B
>Notes</B
></DT
><DD
><P CLASS="j"
>The <SPAN CLASS="kwd"
><SPAN CLASS="cmtt"
>:test-not</SPAN
></SPAN
> <A HREF="26_1_Glossary.html#argument"
><EM CLASS="term"
>argument</EM
></A
> is deprecated. </P
><P CLASS="j"
>The <A HREF="26_1_Glossary.html#function"
><EM CLASS="term"
>function</EM
></A
> <A HREF="f_position.html" CLASS="funref"
><B
>position-if-not</B
></A
> is deprecated.</P
></DD
></DL
></DIV
></DIV
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><DIV CLASS="btmnav"
><A HREF="f_find.html" CLASS="prev"
>&#8592;</A
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