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Hash join: Difference between revisions
→{{header|Mathematica}} / {{header|Wolfram Language}}
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28 4 Glory 35 Buffy
</pre>
=={{header|Nim}}==
<lang Nim>import strformat, tables
type
Data1 = tuple[value: int; key: string]
Data2 = tuple[key: string; value: string]
proc `$`(d: Data1 | Data2): string = &"({d[0]}, {d[1]})"
iterator hashJoin(table1: openArray[Data1]; table2: openArray[Data2]): tuple[a: Data1; b: Data2] =
# Hash phase.
var h: Table[string, seq[Data1]]
for s in table1:
h.mgetOrPut(s.key, @[]).add(s)
# Join phase.
for r in table2:
for s in h[r.key]:
yield (s, r)
let table1 = [(27, "Jonah"),
(18, "Alan"),
(28, "Glory"),
(18, "Popeye"),
(28, "Alan")]
let table2 = [("Jonah", "Whales"),
("Jonah", "Spiders"),
("Alan", "Ghosts"),
("Alan", "Zombies"),
("Glory", "Buffy")]
for row in hashJoin(table1, table2):
echo row.a, " ", row.b</lang>
{{out}}
<pre>(27, Jonah) (Jonah, Whales)
(27, Jonah) (Jonah, Spiders)
(18, Alan) (Alan, Ghosts)
(28, Alan) (Alan, Ghosts)
(18, Alan) (Alan, Zombies)
(28, Alan) (Alan, Zombies)
(28, Glory) (Glory, Buffy)</pre>
=={{header|Oberon-2}}==
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