How to Convert Words to Numbers in C#

Introduction

In this blog, I have described how to convert words to numeric values.

For example:

Input = Three Thousand Five Hundred Sixty Two

Output = 3562

The function is named "ConvertToNumbers" and accepts a parameter of type string and returns a number value containing the words in number.

class WordsToNumbers
{
private static Dictionary<string, long> numberTable = new Dictionary<string, long>{
{"zero",0},{"one",1},{"two",2},{"three",3},{"four",4},{"five",5},{"six",6},
{"seven",7},{"eight",8},{"nine",9},{"ten",10},{"eleven",11},{"twelve",12},
{"thirteen",13},{"fourteen",14},{"fifteen",15},{"sixteen",16},{"seventeen",17},
{"eighteen",18},{"nineteen",19},{"twenty",20},{"thirty",30},{"forty",40},
{"fifty",50},{"sixty",60},{"seventy",70},{"eighty",80},{"ninety",90},
{"hundred",100},{"thousand",1000},{"lakh",100000},{"million",1000000},
{"billion",1000000000},{"trillion",1000000000000},{"quadrillion",1000000000000000},
{"quintillion",1000000000000000000}
};
public static long ConvertToNumbers(string numberString)
{
var numbers = Regex.Matches(numberString, @"\w+").Cast<Match>()
.Select(m => m.Value.ToLowerInvariant())
.Where(v => numberTable.ContainsKey(v))
.Select(v => numberTable[v]);
long acc = 0, total = 0L;
foreach (var n in numbers)
{
if (n >= 1000)
{
total += acc * n;
acc = 0;
}
else if (n >= 100)
{
acc *= n;
}
else acc += n;
}
return (total + acc) * (numberString.StartsWith("minus",
StringComparison.InvariantCultureIgnoreCase) ? -1 : 1);
}
}

Now, call the ConvertToNumbers method.

I hope this is useful for all readers. Happy Coding!