Caio Tarifa - 1 year ago 62

Ruby Question

Can I measure the distance between two strings with Ruby?

**I.e.:**

`compare('Test', 'est') # Returns 1`

compare('Test', 'Tes') # Returns 1

compare('Test', 'Tast') # Returns 1

compare('Test', 'Taste') # Returns 2

compare('Test', 'tazT') # Returns 5

Answer Source

I found this for you:

```
def levenshtein_distance(s, t)
m = s.length
n = t.length
return m if n == 0
return n if m == 0
d = Array.new(m+1) {Array.new(n+1)}
(0..m).each {|i| d[i][0] = i}
(0..n).each {|j| d[0][j] = j}
(1..n).each do |j|
(1..m).each do |i|
d[i][j] = if s[i-1] == t[j-1] # adjust index into string
d[i-1][j-1] # no operation required
else
[ d[i-1][j]+1, # deletion
d[i][j-1]+1, # insertion
d[i-1][j-1]+1, # substitution
].min
end
end
end
d[m][n]
end
[ ['fire','water'], ['amazing','horse'], ["bamerindos", "giromba"] ].each do |s,t|
puts "levenshtein_distance('#{s}', '#{t}') = #{levenshtein_distance(s, t)}"
end
```

That's awesome output: =)

```
levenshtein_distance('fire', 'water') = 4
levenshtein_distance('amazing', 'horse') = 7
levenshtein_distance('bamerindos', 'giromba') = 9
```

Source: http://rosettacode.org/wiki/Levenshtein_distance#Ruby