# Measure the distance between two strings with Ruby?

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
```

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
```