Remove all instances of a string 7 characters long in a textbox in VB - vb.net

Question

I have two text boxes. The first contains this text just like shown.
I need to remove the first 7 characters of each row then show the edited text in the second box.
The first number is different every time so I can't use this
RawText.Text = Replace(RawText.Text, "1757792", " ")
TextFilter.Text = RawText.Text
because the number changes every row.
Is there a way to have a button remove ALL instances of ANY text 7 characters long?
1757792 02 08 09 10 15 21 22 29 34 40 44 46 47 48 53 56 58 68 69 71
1757793 01 07 16 20 22 25 30 36 38 39 42 48 49 51 58 66 70 72 79 80
1757794 01 02 07 09 10 18 29 32 35 36 48 53 54 56 62 65 68 69 71 73
1757795 01 02 06 09 12 18 23 27 30 35 43 52 57 59 60 61 62 73 74 76
1757796 01 11 13 14 18 19 22 31 34 41 45 46 54 57 61 70 71 72 79 80
1757797 01 08 10 18 19 21 32 41 43 44 45 54 61 62 64 66 68 73 74 80
1757798 02 03 06 09 10 23 27 28 33 36 38 41 49 53 60 61 64 73 74 80
1757799 02 12 16 34 36 44 51 52 55 57 58 59 64 71 73 75 76 78 79 80
1757800 05 11 13 17 18 19 23 24 27 31 34 38 39 45 48 61 67 73 79 80
1757801 17 23 29 31 35 38 43 45 48 51 56 57 60 64 65 66 67 73 77 78
1757802 05 06 11 14 17 20 21 27 28 29 33 41 45 49 58 66 67 73 79 80
1757803 06 07 10 11 12 19 20 21 25 30 33 35 38 42 46 51 65 66 75 80
1757804 06 14 16 19 20 23 32 42 43 44 48 52 62 67 68 69 71 72 74 78

Answer 1

You can use string methods like Substring. If you really want to remove the first 7 you can use String.Substring:
Dim txt2Lines = From l In RawText.Lines
Let index = Math.Min(l.Length, 7)
Select l.Substring(index)
txt2.Lines = txt2Lines.ToArray()
This handles also the case that there are also shorter lines.
Note that it doesn't remove the leading space since that is not part of the first seven characters. You could use l.Substring(index).TrimStart().
Another approach is to search the first space and remove everything before that:
Dim txt2Lines = From l In RawText.Lines
Let index = Math.Max(l.IndexOf(" "), 0)
Select l.Substring(index)
txt2.Lines = txt2Lines.ToArray()
String.IndexOf returns -1 if the substring wasn't found, that's why i've used Math.Max(l.IndexOf(" "), 0). In that case the full line should be taken.

Answer 2

You could use String.Split to split the text at the vbCrLf (line break), then use String.SubString to select the string parter starting at index 8, and there you are.
And as GSerg pointed out, if you would like to replace all 7 digit occurences try this:
Dim ResultString As String
Try
ResultString = Regex.Replace(SubjectString, "\d{7}", "", RegexOptions.Singleline)
Catch ex As ArgumentException
'Syntax error in the regular expression
End Try