Hash join: Difference between revisions

</pre>

=={{header|Groovy}}==

<lang Groovy>

def hashJoin(s, r) {

def hashed = s.groupBy { sItem -> sItem.name }

def q = [] as Set

r.each { rItem ->

def join = hashed[rItem.name]

join.each { sItem ->

q << sItem.plus(rItem)

}

}

q

}

</lang>

Sample run:

<pre>

def s = [[age: 27, name: 'Jonah'],

[age: 18, name: 'Alan'],

[age: 28, name: 'Glory'],

[age: 18, name: 'Popeye'],

[age: 28, name: 'Alan']]

def r = [[name: 'Jonah', nemesis: 'Whales'],

[name: 'Jonah', nemesis: 'Spiders'],

[name: 'Alan', nemesis: 'Ghosts'],

[name: 'Alan', nemesis: 'Zombies'],

[name: 'Glory', nemesis: 'Buffy']]

hashJoin(s, r).sort {it.name}.each { println it }

</pre>

produces:

<pre>

[age:18, name:Alan, nemesis:Ghosts]

[age:28, name:Alan, nemesis:Ghosts]

[age:18, name:Alan, nemesis:Zombies]

[age:28, name:Alan, nemesis:Zombies]

[age:28, name:Glory, nemesis:Buffy]

[age:27, name:Jonah, nemesis:Whales]

[age:27, name:Jonah, nemesis:Spiders]