Levenshtein distance/Alignment: Difference between revisions

</pre>

=={{header|Wren}}==

{{trans|Kotlin}}

{{libheader|Wren-str}}

{{libheader|Wren-math}}

<lang ecmascript>import "/str" for Str

import "/math" for Math

var levenshteinAlign = Fn.new { |a, b|

a = Str.lower(a)

b = Str.lower(b)

var costs = List.filled(a.count+1, null)

for (i in 0..a.count) costs[i] = List.filled(b.count+1, 0)

for (j in 0..b.count) costs[0][j] = j

for (i in 1..a.count) {

costs[i][0] = i

for (j in 1..b.count) {

var temp = costs[i - 1][j - 1] + ((a[i - 1] == b[j - 1]) ? 0 : 1)

costs[i][j] = Math.min(1 + Math.min(costs[i - 1][j], costs[i][j - 1]), temp)

}

}

// walk back through matrix to figure out path

var aPathRev = ""

var bPathRev = ""

var i = a.count

var j = b.count

while (i != 0 && j != 0) {

var temp = costs[i - 1][j - 1] + ((a[i - 1] == b[j - 1]) ? 0 : 1)

var cij = costs[i][j]

if (cij == temp) {

i = i - 1

aPathRev = aPathRev + a[i]

j = j - 1

bPathRev = bPathRev + b[j]

} else if (cij == 1 + costs[i-1][j]) {

i = i - 1

aPathRev = aPathRev + a[i]

bPathRev = bPathRev + "-"

} else if (cij == 1 + costs[i][j-1]) {

aPathRev = aPathRev + "-"

j = j - 1

bPathRev = bPathRev+ b[j]

}

}

return [aPathRev[-1..0], bPathRev[-1..0]]

}

var result = levenshteinAlign.call("place", "palace")

System.print(result[0])

System.print(result[1])

System.print()

result = levenshteinAlign.call("rosettacode","raisethysword")

System.print(result[0])

System.print(result[1])</lang>

{{out}}

<pre>

p-lace

palace

r-oset-tacode

raisethysword