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# c# -find roman numerals and convert to int

hello everybody.. im in a bit of problem now..

i need to find roman numerals in a string and convert it to int eg:

"XIV VARA CIVIL" = int 14
"VARA CIVIL XX" = int 20

does anyone know if there is any method for it in web? maybe a regex to find could work but i have no clue or time to make such conversor

thx for the help!

0
eguilherme
1 Solution

Commented:
Will the numerals always be at either the beginning or end of the string?
Will "VARA CIVIL" always be in the string?
0

Author Commented:
not really.. that was just a sample..

the roman numerals could be anywhere in the string (most of the time they are at either the beggining or at the end, but i cant be sure if that would be always the case)

but the text it will be different everytime.

is it possible to do such thing ?
0

Commented:
Since the roman numeral will always be a word, first break the string into it's component words.

string y = "VARA CIVIL XX";
string[] x = y.Split(' ');

this makes anarray of strings
x[0] = "VERA"
x[1] = "CIVIL"
x[2] = "XX"

then try each value in the string array x to see if it is a valid roman numeral.

Here is a link to an example of how to convert a roman numeral to a number.
http://www.blackwasp.co.uk/RomanToNumber.aspx
0

IT GuruCommented:
You could do a regex match with pattern:
(?i)\b(?=[ivxlcdm]+)M{0,4}(?:CM|CD|D?C{0,3})(?:XC|XL|L?X{0,3})(?:IX|IV|V?I{0,3})\b

Based on, but slightly modified from, a pattern from: http://stackoverflow.com/questions/267399/how-do-you-match-only-valid-roman-numerals-with-a-regular-expression

That would capture only valid roman numerals, I believe - then you'd have to convert them to an integer.
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Commented:
Once you have just the valid roman numerals, here is some javascript that converts both to and from roman numerals.  It is trivial to switch this to C# or whatever you want.
``````<script language="javascript">

<!--

function Level(i, v, x)
{
this.i = i;
this.v = v;
this.x = x
}

levels = new Array();

levels[0] = new Level('I', 'V', 'X');
levels[1] = new Level('X', 'L', 'C');
levels[2] = new Level('C', 'D', 'M');

function calcDigit(d, l)
{
if (l > 2)
{
str = '';
for (var m = 1; m <= d * Math.pow(10, l - 3) ; m++)
str += 'M';
return str
}

else
if (d == 1)
return levels[l].i
else
if (d == 2)
return levels[l].i + levels[l].i
else
if (d == 3)
return levels[l].i + levels[l].i + levels[l].i
else
if (d == 4)
return levels[l].i + levels[l].v
else
if (d == 5)
return levels[l].v
else
if (d == 6)
return levels[l].v + levels[l].i
else
if (d == 7)
return levels[l].v + levels[l].i + levels[l].i
else
if (d == 8)
return levels[l].v + levels[l].i + levels[l].i + levels[l].i
else
if (d == 9)
return levels[l].i + levels[l].x
else
return ''
}

function toRoman(n)
{
var r = ''
for (var c = 0; c < n.length; c++)
r += calcDigit(eval(n.charAt(c)), n.length - c - 1);
return r
}

function fromRoman(n)
{
var r = 0

for (var c = 0; c < n.length; c++)
{
var chr = n.charAt(c).toLowerCase();
if (c < n.length - 1)
var next = n.charAt(c + 1).toLowerCase()
else
var next = '';

if (c > 0)
var prev = n.charAt(c - 1).toLowerCase()
else
var prev = '';

if (chr == 'i')
{
if (next == 'v')
r += 4
else
if (next == 'x')
r += 9
else
r += 1;
continue
}

if (chr == 'v')
{
if (prev != 'i')
r += 5;
continue
}

if (chr == 'x')
{
if (prev != 'i')
if (next == 'l')
r += 40
else
if (next == 'c')
r += 90
else
r += 10;
continue
}

if (chr == 'l')
{
if (prev != 'x')
r += 50;
continue
}

if (chr == 'c')
{
if (prev != 'x')
if (next == 'd')
r += 400
else
if (next == 'm')
r += 900
else
r += 100;
continue
}

if (chr == 'd')
{
if (prev != 'c')
r += 500;
continue
}

if (chr == 'm')
{
if (prev != 'c')
r += 1000;
continue

}
}

return r

}

function isNuneric(str)
{
for (var c = 0; c < str.length; c++)
{
var chr = str.charAt(c);
if (chr != '0' & chr != '1' & chr != '2' & chr != '3' & chr != '4' & chr != '5' & chr != '6' & chr != '7' & chr != '8' & chr != '9')
return false
}
return true
}

function get(f)
{

var n = f.elements[0].value

if (!isNuneric(n))
{
for (var c = 0; c < n.length; c++)
{
var chr = n.charAt(c).toLowerCase();
if (chr != 'i' & chr != 'v' & chr != 'x' & chr != 'l' & chr != 'c' & chr != 'd' & chr != 'm')
{
return false
}
}
mode = 'fromRoman'
}
else
mode = 'toRoman';

if (mode == 'toRoman')
f.elements[0].value = toRoman(f.elements[0].value)
else
f.elements[0].value = fromRoman(f.elements[0].value);

return false
}

function go(site)
{
if (site.selectedIndex>0)
top.location=site.options[site.selectedIndex].value
}

function foc()
{
if (navigator.userAgent.indexOf('Mozilla/3') != -1 | navigator.userAgent.indexOf('Mozilla/4') != -1)
document.forms[0].elements[0].focus()
}

//-->

</script>
``````
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