How to append an integer to an array in visual basic

Question

I'm making a program that takes a sentence with no punctuation as an input, then searches for how many occurrences there are of a specific word.

 Dim sntnce As String
    Dim srchWord As String
    Dim words As String()
    Dim word As String
    Dim count As Integer
    Dim index As New System.Text.StringBuilder()

    Console.WriteLine("Enter your sentence: ")
    sntnce = Console.ReadLine()
    sntnce = LCase(sntnce)

    Console.WriteLine("Enter the word you want to find the position of: ")
    srchWord = Console.ReadLine()
    srchWord = LCase(srchWord)

    words = sntnce.Split(New Char() {" "c})
    Console.WriteLine(" ")

    For Each word In words
        If word = srchWord Then
            index.Append(count)
            count += 1
        Else
            count += 1
        End If
    Next

    Console.WriteLine("Your word appears in the position(s)...")
    Console.WriteLine(index)
    Console.ReadLine()

The for loop takes the index of a word if found in a sentence and appends it to a string, but I would like to append it to an array so that the values for indexes can be outputted separately, however I can't find any solutions that help. How can I do this? Thanks

You would use a List<int> object for a variable size array. — John Alexiou
– John Alexiou, Commented Mar 19, 2017 at 15:04

John Alexiou · Accepted Answer · 2017-03-19 18:04:04Z

1

Arrays are of fixed size only. When dealing with collections that you want to add, remove or insert use List(Of T).

I think what you want is the following:

Sub Main()
    Dim sntnce As String
    Dim srchWord As String
    Dim words As String()
    Dim word As String
    Dim count As Integer

    Console.WriteLine("Enter your sentence: ")
    sntnce = Console.ReadLine()
    sntnce = LCase(sntnce)

    Console.WriteLine("Enter the word you want to find the position of: ")
    srchWord = Console.ReadLine()
    srchWord = LCase(srchWord)

    words = sntnce.Split(New Char() {" "c})
    Console.WriteLine(" ")
    ' Create an expandable list of integers 'index_list'
    Dim index_list As New List(Of Integer)
    For index As Integer = 1 To words.Length
        ' It's recommened to use `Equals()` for string equality instead of `=`
        ' Arrays in VB.NET are 0-based so the i-th elements is located in `list(i-1)`
        If words(index - 1).Equals(srchWord) Then
            ' Add index to list if there is a match
            index_list.Add(index)
        End If
    Next
    ' Create a fixed array of strings to hold the character representation of the integer index array. 
    ' Since I know the size I can use an array instead of a list.
    Dim index_list_string As String() = New String(index_list.Count) {}
    For index As Integer = 1 To index_list.Count
        ' One to one mapping of integer to string
        index_list_string(index - 1) = index_list(index - 1).ToString()
    Next
    Console.WriteLine("Your word appears in the position(s)...")
    ' Take the array of strings and combine it into one string with commas in between using the `.Join()` function
    ' For example `{"A","B","C"} => "A, B, C"
    Console.WriteLine(String.Join(", ", index_list_string))
    Console.ReadLine()
End Sub

edited Mar 19, 2017 at 18:04

answered Mar 19, 2017 at 15:19

John Alexiou

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5 Comments

Blackman123 Over a year ago

That is absolutely perfect. Thanks!

Blackman123 Over a year ago

Could I have a little explanation of the things you've added. I'm can't quite wrap my head around everything that you've done.

John Alexiou Over a year ago

Better yet, I added comments to the code for your benefit.

Blackman123 Over a year ago

Even better! Thanks!

John Alexiou Over a year ago

Once you learn LINQ that last parts greatly simplify to something like String.Join(", ", index_list.Select(Function(index) index.ToString()))

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