Counting vowels in a string c#

Question

I am making a program to analyse features of a user inputted sentence. To count the vowels in the sentence I have made a very messy sequence of foreach loops here:

foreach (char v1 in input)
{
    if (v1 == 'a')
    {
        vcounter++;
    }
}
foreach (char v2 in input)
{
    if (v2 == 'e')
    {
        vcounter++;
    }
}
foreach (char v3 in input)
{
    if (v3 == 'i')
    {
        vcounter++;
    }
}
foreach (char v4 in input)
{
    if (v4 == 'o')
    {
        vcounter++;
    }
}
foreach (char v5 in input)
{
    if (v5 == 'u')
    {
        vcounter++;
    }
}

I then take the vcounter and display it as the result. I am very new to c# and I am wondering if anyone can suggest a better way of doing this?.

Hint: consider a dictionary – Mitch Wheat Dec 22 '16 at 07:30 — Mitch Wheat, Dec 22 '16 at 07:30

Maciej Kasprzak · Accepted Answer · 2016-12-22T07:42:59.173

8

Store your vowels in array like this:

private readonly char[] vowels = new char[] { 'a', 'e', 'i', 'o', 'u' };

And then count them:

public int CountVowels(string text)
{
    return text.ToLower().Count(x => vowels.Contains(x));
}

edited Dec 22 '16 at 07:42

answered Dec 22 '16 at 07:34

Maciej Kasprzak

929
6
17

If you create a HashSet instead of an array, it will be faster :) Contains in array is really full scan. – Ilya Chernomordik Dec 22 '16 at 07:37
1

@IlyaChernomordik for tiny sets full scan might be actually faster. Anyway it's a micro-optimization. ;-) – Crozin Dec 22 '16 at 07:39

score 0 · Answer 2 · answered Dec 22 '16 at 07:34

If your are using .NET 3.5 or higher you could use LINQ for this.

vcounter += input.Count(v => v == 'a');
vcounter += input.Count(v => v == 'e');
vcounter += input.Count(v => v == 'i');
vcounter += input.Count(v => v == 'o');
vcounter += input.Count(v => v == 'u');

For this you must import LINQ in your document.

using System.Linq;

score 0 · Answer 3 · answered Dec 22 '16 at 07:34

You can try with following code:

const string vowels = "aeiou";
var count = input.Count(chr => vowels.Contains(char.ToLower(chr)));

or

for (int i = 0; i < input.Length; i++)
    {
        if (input[i]  == 'a' || input[i] == 'e' || input[i] == 'i' || input[i] == 'o' || input[i] == 'u')
        {
            count++;
        }
    }

score 0 · Answer 4 · answered Dec 22 '16 at 07:36

0

Store your vowels in list :

List<Char> vowels = new List<char>() { 'a', 'e', 'i', 'o', 'u' };

And count like this :

int vcounter = 0;
foreach (char chr in input)
{
   if (vowels.Contains(chr))
   {
       vcounter++;
   }
}

answered Dec 22 '16 at 07:36

Sameer

2,143
1
16
22

score 0 · Answer 5 · answered Dec 22 '16 at 07:39

Try this:

var text = "hfdaa732ibgedsoju";
var vowels = new[] { 'a', 'e', 'i', 'o', 'u' };
var vowelFrequency = text.Where(c => vowels.Contains(c))
                         .GroupBy(c => c)
                         .ToDictionary(g => g.Key, g.Value.Count());

Will create a dictionary similar to Maksim's answer but only with vowels.

Use vowelFrequency.Sum(vf => vf.Value) to get the total count of vowels in the string.

Hafthor · Answer 6 · 2016-12-22T07:47:36.310

0

Not very efficient, but short

using System.Text.RegularExpressions;

// ...

var vcounter = Regex.Matches(input, "[aeiou]", RegexOptions.IgnoreCase).Count;

edited Dec 22 '16 at 07:47

answered Dec 22 '16 at 07:41

Hafthor

16,358
9
56
65

score 0 · Answer 7 · edited Dec 22 '16 at 09:08

0

You can just use a regular expression:

vcounter = Regex.Matches(input, "a|e|i|o|u", RegexOptions.IgnoreCase).Count;

edited Dec 22 '16 at 09:08

thomasb

5,816
10
57
92

answered Dec 22 '16 at 07:45

Andy Lamb

2,151
20
22

you don't need to escape the input. that's only if you are trying to turn a normal string into a match expression. – Hafthor Dec 22 '16 at 07:46
Good point! I've updated the answer. – Andy Lamb Dec 22 '16 at 08:04

score 0 · Answer 8 · answered Dec 22 '16 at 07:45

You can maintain in this function. I created a array which contains some letters.

 private void button1_Click(object sender, EventArgs e)
        {
            string [] array = { "a", "b", "c", "d" };
            int vcounter = 0;
            foreach (var item in array)
            {
                if (item.Contains("a") || item.Contains("e") || item.Contains("i")) //You can add the other volwes 
                {
                    vcounter++;
                }
            }
            MessageBox.Show("Count of vowels : " + vcounter.ToString());
        }

Counting vowels in a string c#

8 Answers8