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<link type="text/css" rel="stylesheet" href="http://pasterack.org/scribble.css"/><link type="text/css" rel="stylesheet" href="http://pasterack.org/racket.css"/><link type="text/css" rel="stylesheet" href="http://fonts.googleapis.com/css?family=Droid+Sans+Mono"/><div style="font-family:'Droid Sans Mono',monospace;background-color:transparent"><ol start="0" style="font-size:70%;color:#A0A0A0"><li><span style="font-family:'Droid Sans Mono',monospace;font-size:125%"><a class="RktModLink" data-pltdoc="x" href="http://docs.racket-lang.org/guide/Module_Syntax.html#%28part._hash-lang%29"><span class="RktMod">#lang</span></a><span class="RktMeta"></span><span class="hspace"> </span><span class="RktMeta"></span><a class="RktModLink" data-pltdoc="x" href="http://docs.racket-lang.org/reference/index.html"><span class="RktSym">racket/base</span></a><span class="RktMeta"></span></span></li><li><span style="font-family:'Droid Sans Mono',monospace;font-size:125%"><span class="RktMeta"></span><span class="RktPn">(</span><span class="RktSym"><a class="RktStxLink" data-pltdoc="x" href="http://docs.racket-lang.org/reference/require.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._require%29%29">require</a></span><span class="RktMeta"></span><span class="hspace"> </span><span class="RktMeta"></span><span class="RktSym">racket/dict</span><span class="RktPn">)</span><span class="RktMeta"></span></span></li><li><span style="font-family:'Droid Sans Mono',monospace;font-size:125%"><span class="RktMeta"></span><span class="RktCmt">;;</span><span class="hspace"> </span><span class="RktCmt">An</span><span class="hspace"> </span><span class="RktCmt">association</span><span class="hspace"> </span><span class="RktCmt">list</span><span class="hspace"> </span><span class="RktCmt">is</span><span class="hspace"> </span><span class="RktCmt">a</span><span class="hspace"> </span><span class="RktCmt">`dict?`,</span><span class="RktMeta"></span></span></li><li><span style="font-family:'Droid Sans Mono',monospace;font-size:125%"><span class="RktMeta"></span><span class="RktCmt">;;</span><span class="hspace"> </span><span class="RktCmt">so</span><span class="hspace"> </span><span class="RktCmt">you</span><span class="hspace"> </span><span class="RktCmt">can</span><span class="hspace"> </span><span class="RktCmt">pass</span><span class="hspace"> </span><span class="RktCmt">an</span><span class="hspace"> </span><span class="RktCmt">association</span><span class="hspace"> </span><span class="RktCmt">list</span><span class="hspace"> </span><span class="RktCmt">to</span><span class="hspace"> </span><span class="RktCmt">functions</span><span class="hspace"> </span><span class="RktCmt">like</span><span class="hspace"> </span><span class="RktCmt">`dict-ref`</span><span class="RktMeta"></span></span></li><li><span style="font-family:'Droid Sans Mono',monospace;font-size:125%"><span class="RktMeta"></span><span class="RktCmt">;;</span><span class="hspace"> </span><span class="RktCmt">http://docs.racket-lang.org/reference/dicts.html</span><span class="RktMeta"></span></span></li><li><span style="font-family:'Droid Sans Mono',monospace;font-size:125%"><span class="RktMeta"> </span></span></li><li><span style="font-family:'Droid Sans Mono',monospace;font-size:125%"><span class="RktMeta"></span><span class="RktPn">(</span><span class="RktSym"><a class="RktStxLink" data-pltdoc="x" href="http://docs.racket-lang.org/reference/for.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._for%2Ffold%29%29">for/fold</a></span><span class="RktMeta"></span><span class="hspace"> </span><span class="RktMeta"></span><span class="RktPn">(</span><span class="RktPn">[</span><span class="RktSym">acc</span><span class="RktMeta"></span><span class="hspace"> </span><span class="RktMeta"></span><span class="RktSym"><a class="RktStxLink" data-pltdoc="x" href="http://docs.racket-lang.org/reference/quote.html#%28form._%28%28quote._~23~25kernel%29._quote%29%29">'</a></span><span class="RktPn">(</span><span class="RktPn">)</span><span class="RktPn">]</span><span class="RktPn">)</span><span class="RktMeta"></span></span></li><li><span style="font-family:'Droid Sans Mono',monospace;font-size:125%"><span class="RktMeta"></span><span class="hspace"> </span><span class="RktMeta"></span><span class="RktPn">(</span><span class="RktPn">[</span><span class="RktSym">key</span><span class="RktMeta"></span><span class="hspace"> </span><span class="RktMeta"></span><span class="RktPn">(</span><span class="RktSym"><a class="RktValLink" data-pltdoc="x" href="http://docs.racket-lang.org/reference/sequences.html#%28def._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._in-list%29%29">in-list</a></span><span class="RktMeta"></span><span class="hspace"> </span><span class="RktMeta"></span><span class="RktSym"><a class="RktStxLink" data-pltdoc="x" href="http://docs.racket-lang.org/reference/quote.html#%28form._%28%28quote._~23~25kernel%29._quote%29%29">'</a></span><span class="RktPn">(</span><span class="RktVal">1</span><span class="RktMeta"></span><span class="hspace"> </span><span class="RktMeta"></span><span class="RktVal">2</span><span class="RktMeta"></span><span class="hspace"> </span><span class="RktMeta"></span><span class="RktVal">3</span><span class="RktPn">)</span><span class="RktPn">)</span><span class="RktPn">]</span><span class="RktPn">)</span><span class="RktMeta"></span></span></li><li><span style="font-family:'Droid Sans Mono',monospace;font-size:125%"><span class="RktMeta"></span><span class="hspace"> </span><span class="RktMeta"></span><span class="RktPn">(</span><span class="RktSym"><a class="RktValLink" data-pltdoc="x" href="http://docs.racket-lang.org/reference/dicts.html#%28def._%28%28lib._racket%2Fdict..rkt%29._dict-set%29%29">dict-set</a></span><span class="RktMeta"></span><span class="hspace"> </span><span class="RktMeta"></span><span class="RktSym">acc</span><span class="RktMeta"></span><span class="hspace"> </span><span class="RktMeta"></span><span class="RktSym">key</span><span class="RktMeta"></span><span class="hspace"> </span><span class="RktMeta"></span><span class="RktSym">key</span><span class="RktPn">)</span><span class="RktPn">)</span><span class="RktMeta"></span></span></li><li><span style="font-family:'Droid Sans Mono',monospace;font-size:125%"><span class="RktMeta"> </span></span></li><li><span style="font-family:'Droid Sans Mono',monospace;font-size:125%"><span class="RktMeta"></span><span class="RktCmt">;;</span><span class="hspace"> </span><span class="RktCmt">Preserves</span><span class="hspace"> </span><span class="RktCmt">order</span><span class="hspace"> </span><span class="RktCmt">for</span><span class="hspace"> </span><span class="RktCmt">me,</span><span class="hspace"> </span><span class="RktCmt">but</span><span class="hspace"> </span><span class="RktCmt">IDK</span><span class="hspace"> </span><span class="RktCmt">if</span><span class="hspace"> </span><span class="RktCmt">that's</span><span class="hspace"> </span><span class="RktCmt">always</span><span class="hspace"> </span><span class="RktCmt">true</span><span class="RktMeta"></span></span></li></ol><p>=></p><blockquote><table style="font-size:90%;table-layout:fixed;width:100%;word-wrap:break-word"><tr><td><p><span class="RktRes">'((1 . 1) (2 . 2) (3 . 3))</span></p></td></tr></table></blockquote></div>
racket/dict example
#lang
racket/base
(
require
racket/dict
)
;;
An
association
list
is
a
`dict?`,
;;
so
you
can
pass
an
association
list
to
functions
like
`dict-ref`
;;
http://docs.racket-lang.org/reference/dicts.html
(
for/fold
(
[
acc
'
(
)
]
)
(
[
key
(
in-list
'
(
1
2
3
)
)
]
)
(
dict-set
acc
key
key
)
)
;;
Preserves
order
for
me,
but
IDK
if
that's
always
true
=>
'((1 . 1) (2 . 2) (3 . 3))