Not allow to use special characters within string - vb.net

have some method which guard user to allow only letters, digits, - and single spaces. Saying letters i thought that letters only (a-z and A-Z) but without e.g ę, Ę, ą Ą, ś Ś, ż Ż etc... Can you please help me to fix my below code to check also that one? (not using regex)
For Each c As Char In txtSymbol.Text
If Not Char.IsLetterOrDigit(c) AndAlso c <> "-"c AndAlso c <> " " Then
MessageBox.Show("Only lower/upper letters, digits, - and single spaces are allowed"", "Warning", MessageBoxButtons.OK, MessageBoxIcon.Warning)
Exit Try
End If
Next
For further discussion:
'--We elping user with leading and ending spaces to be removed and more than one space in same placed to be convert to only one space
Dim str As String = txtNazwa.Text.Trim 'deleting leading and ending spaces
While str.Contains(" ") 'deleting more than one space in same place
str = str.Replace(" ", " ")
End While
txtNazwa.Text = str 'corrected one we passed to textbox
'Now we checking further for only those can be presented to pass test:
'--> single space
'--> letters a-z A-Z
'--> digits
'--> -
Dim pattern As String = "^([a-zA-Z0-9-]+\s)*[a-zA-Z0-9-]+$"
Dim r As New Regex(pattern)
If Not r.IsMatch(str) Then
Exit Try
End If

You can try to use this regex:
^([a-zA-Z0-9-]+\s)*[a-zA-Z0-9-]+$
Regex Demo
In your code you can try it like this:
Dim str As String = "^[a-zA-Z0-9 ]*$"
Dim r As New Regex(str)
Console.WriteLine(r.IsMatch("yourInputString"))

Related

VB.NET - Delete excess white spaces between words in a sentence

I'm a programing student, so I've started with vb.net as my first language and I need some help.
I need to know how I delete excess white spaces between words in a sentence, only using these string functions: Trim, instr, char, mid, val and len.
I made a part of the code but it doesn't work, Thanks.
enter image description here
Knocked up a quick routine for you.
Public Function RemoveMyExcessSpaces(str As String) As String
Dim r As String = ""
If str IsNot Nothing AndAlso Len(str) > 0 Then
Dim spacefound As Boolean = False
For i As Integer = 1 To Len(str)
If Mid(str, i, 1) = " " Then
If Not spacefound Then
spacefound = True
End If
Else
If spacefound Then
spacefound = False
r += " "
End If
r += Mid(str, i, 1)
End If
Next
End If
Return r
End Function
I think it meets your criteria.
Hope that helps.
Unless using those VB6 methods is a requirement, here's a one-line solution:
TextBox2.Text = String.Join(" ", TextBox1.Text.Split(New Char() {" "c}, StringSplitOptions.RemoveEmptyEntries))
Online test: http://ideone.com/gBbi55
String.Split() splits a string on a specific character or substring (in this case a space) and creates an array of the string parts in-between. I.e: "Hello There" -> {"Hello", "There"}
StringSplitOptions.RemoveEmptyEntries removes any empty strings from the resulting split array. Double spaces will create empty strings when split, thus you'll get rid of them using this option.
String.Join() will create a string from an array and separate each array entry with the specified string (in this case a single space).
There is a very simple answer to this question, there is a string method that allows you to remove those "White Spaces" within a string.
Dim text_with_white_spaces as string = "Hey There!"
Dim text_without_white_spaces as string = text_with_white_spaces.Replace(" ", "")
'text_without_white_spaces should be equal to "HeyThere!"
Hope it helped!

Removing All Spaces in String

I created a macro for removing all whitespace in a string, specifically an email address. However it only removes about 95% of the whitespace, and leaves a few.
My code:
Sub NoSpaces()
Dim w As Range
For Each w In Selection.Cells
w = Replace(w, " ", "")
Next
End Sub
Things I have tried to solve the issue include:
~ Confirmed the spaces are indeed spaces with the Code function, it is character 32 (space)
~ Used a substitute macro in conjuction with the replace macro
~ Have additional macro utilizing Trim function to remove leading and trailing whitespace
~ Made a separate macro to test for non-breaking spaces (character 160)
~ Used the Find and Replace feature to search and replace spaces with nothing. Confirmed working.
I only have one cell selected when I run the macro. It selects and goes through all the cells because of the Selection.Cells part of the code.
A few examples:
1 STAR MOVING # ATT.NET
322 TRUCKING#GMAIL.COM
ALEZZZZ#AOL. COM.
These just contain regular whitespace, but are skipped over.
Just use a regular expression:
'Add a reference to Microsoft VBScript Regular Expressions 5.5
Public Function RemoveWhiteSpace(target As String) As String
With New RegExp
.Pattern = "\s"
.MultiLine = True
.Global = True
RemoveWhiteSpace = .Replace(target, vbNullString)
End With
End Function
Call it like this:
Sub NoSpaces()
Dim w As Range
For Each w In Selection.Cells
w.Value = RemoveWhiteSpace(w.Value)
Next
End Sub
Try this:
Sub NoSpaces()
Selection.Replace " ", ""
End Sub
Use "Substitute"
Example...
=SUBSTITUTE(C1:C18," ","")
Because you assume that Selection.Cells includes all cells on the sheet.
Cells.Replace " ", ""
And to add to the excellent advice from all the great contributors, try the
TRIM or LTRIM, or RTRIM and you can read more about these functions here:
https://msdn.microsoft.com/en-us/library/office/gg278916.aspx
Now this does not remove embedded spaces (spaces in between the letters) but it will remove any leading and trailing spaces.
Hope this helps.
Space Problem with Excel
ok, the only way i see this two types of space is by converting their Ascii code value of which I do it here
now to explain this function i made, it will just filter the string character by character checking if its equal to the two types of space i mentioned. if not it will concatenate that character into the string which will be the final value after the loop. hope this helps. Thanks.
Function spaceremove(strs) As String
Dim str As String
Dim nstr As String
Dim sstr As String
Dim x As Integer
str = strs
For x = 1 To VBA.Len(str)
sstr = Left(Mid(str, x), 1)
If sstr = " " Or sstr = " " Then
Else
nstr = nstr & "" & sstr
End If
Next x
spaceremove = nstr
End Function
I copied a HTML table with data and pasted in excel but the cells were filled with unwanted space and all methods posted here didn't work so I debugged and I discovered that it wasn't actually space chars (ASCII 32) it was Non-breaking space) (ASCII 160) or HTML
So to make it work with that Non-breaking space char I did this:
Sub NoSpaces()
Dim w As Range
For Each w In Selection.Cells
w.Value = Replace(w.Value, " ", vbNullString)
w.Value = Replace(w.Value, Chr(160), vbNullString)
Next
End Sub

Cleaning text strings in vb

I am trying to clean up a string from a text field that will be part of sql query.
I have created a function:
Private Function cleanStringToProperCase(dirtyString As String) As String
Dim cleanedString As String = dirtyString
'removes all but non alphanumeric characters except #, - and .'
cleanedString = Regex.Replace(cleanedString, "[^\w\.#-]", "")
'trims unecessary spaces off left and right'
cleanedString = Trim(cleanedString)
'replaces double spaces with single spaces'
cleanedString = Regex.Replace(cleanedString, " ", " ")
'converts text to upper case for first letter in each word'
cleanedString = StrConv(cleanedString, VbStrConv.ProperCase)
'return the nicely cleaned string'
Return cleanedString
End Function
But when I try to clean any text with two words, it strips ALL white space out. "daz's bike" becomes "Dazsbike". I am assuming I need to modify the following line:
cleanedString = Regex.Replace(cleanedString, "[^\w\.#-]", "")
so that it also lets single white space characters remain. Advice on how to do so is greatly received as I cannot find it on any online tutorials or on the MSDN site (http://msdn.microsoft.com/en-us/library/844skk0h(v=vs.110).aspx)
Use "[^\w\.,#\-\' ]" instead of your pattern string.
Also, I would use
Regex.Replace(cleanedString, " +", " ")
instead of
Regex.Replace(cleanedString, " ", " ")
Or, if you are not a big fan of regex...
Private Function cleanStringToProperCase(dirtyString As String) As String
'specify valid characters
Dim validChars As String = " #-.0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
'removes all but validChars'
Dim cleanedString As String = dirtyString.Where(Function(c) validChars.Contains(c)).ToArray
Dim myTI As Globalization.TextInfo = New Globalization.CultureInfo(Globalization.CultureInfo.CurrentCulture.Name).TextInfo
'return the nicely cleaned string'
Return myTI.ToTitleCase(cleanedString.Trim)
End Function

Comparing character only to character at end of string

I am writing a program in Visual Basic 2010 that lists how many times a word of each length occurs in a user-inputted string. Although most of the program is working, I have one problem:
When looping through all of the characters in the string, the program checks whether there is a next character (such that the program does not attempt to loop through characters that do not exist). For example, I use the condition:
If letter = Microsoft.VisualBasic.Right(input, 1) Then
Where letter is the character, input is the string, and Microsoft.VisualBasic.Right(input, 1) extracts the rightmost character from the string. Thus, if letter is the rightmost character, the program will cease to loop through the string.
This is where the problems comes in. Let us say the string is This sentence has five words. The rightmost character is an s, but an s is also the fourth and sixth character. That means that the first and second s will break the loop just as the others will.
My questions is whether there is a way to ensure that only the last s, or whatever character is the last one in the string can break the loop.
There are a few methods you can use for this, one as Neolisk shows; here are a couple of others:
Dim breakChar As Char = "s"
Dim str As String = "This sentence has five words"
str = str.Replace(".", " ")
str = str.Replace(",", " ")
str = str.Replace(vbTab, " ")
' other chars to replace
Dim words() As String = str.ToLower.Split(New Char() {" "}, StringSplitOptions.RemoveEmptyEntries)
For Each word In words
If word.StartsWith(breakChar) Then Exit For
Console.WriteLine("M1 Word: ""{0}"" Length: {1:N0}", word, word.Length)
Next
If you need to loop though chars for whatever reason, you can use something like this:
Dim breakChar As Char = "s"
Dim str As String = "This sentence has five words"
str = str.Replace(".", " ")
str = str.Replace(",", " ")
str = str.Replace(vbTab, " ")
' other chars to replace
'method 2
Dim word As New StringBuilder
Dim words As New List(Of String)
For Each c As Char In str.ToLower.Trim
If c = " "c Then
If word.Length > 0 'support multiple white-spaces (double-space etc.)
Console.WriteLine("M2 Word: ""{0}"" Length: {1:N0}", word.ToString, word.ToString.Length)
words.Add(word.ToString)
word.Clear()
End If
Else
If word.Length = 0 And c = breakChar Then Exit For
word.Append(c)
End If
Next
If word.Length > 0 Then
words.Add(word.ToString)
Console.WriteLine("M2 Word: ""{0}"" Length: {1:N0}", word.ToString, word.ToString.Length)
End If
I wrote these specifically to break on the first letter in a word as you ask, adjust as needed.
VB.NET code to calculate how many times a word of each length occurs in a user-inputted string:
Dim sentence As String = "This sentence has five words"
Dim words() As String = sentence.Split(" ")
Dim v = From word As String In words Group By L = word.Length Into Group Order By L
Line 2 may need to be adjusted to remove punctuation characters, trim extra spaces etc.
In the above example, v(i) contains word length, and v(i).Group.Count contains how many words of this length were encountered. For debugging purposes, you also have v(i).Group, which is an array of String, containing all words belonging to this group.

Get only the line of text that contains the given word VB2010.net

I have a text file on my website and I download the whole string via webclient.downloadstring.
The text file contains this :
cookies,dishes,candy,(new line)
back,forward,refresh,(new line)
mail,media,mute,
This is just an example it's not the actual string , but it will do for help purposes.
What I want is I want to download the whole string , find the line that contains the word that was entered by the user in a textbox, get that line into a string, then I want to use the string.split with as delimiter the "," and output each word that is in the string into an richtextbox.
Now here is the code that I have used (some fields are removed for privacy reasons).
If TextBox1.TextLength > 0 Then
words = web.DownloadString("webadress here")
If words.Contains(TextBox1.Text) Then
'retrieval code here
Dim length As Integer = TextBox1.TextLength
Dim word As String
word = words.Substring(length + 1) // the plus 1 is for the ","
Dim cred() As String
cred = word.Split(",")
RichTextBox1.Text = "Your word: " + cred(0) + vbCr + "Your other word: " + cred(1)
Else
MsgBox("Sorry, but we could not find the word you have entered", MsgBoxStyle.Critical)
End If
Else
MsgBox("Please fill in an word", MsgBoxStyle.Critical)
End If
Now it works and no errors , but it only works for line 1 and not on line 2 or 3
what am I doing wrong ?
It's because the string words also contains the new line characters that you seem to be omitting in your code. You should first split words with the delimiter \n (or \r\n, depending on the platform), like this:
Dim lines() As String = words.Split("\n")
After that, you have an array of strings, each element representing a single line. Loop it through like this:
For Each line As String In lines
If line.Contains(TextBox1.Text) Then
'retrieval code here
End If
Next
Smi's answer is correct, but since you're using VB you need to split on vbNewLine. \n and \r are for use in C#. I get tripped up by that a lot.
Another way to do this is to use regular expressions. A regular expression match can both find the word you want and return the line that contains it in a single step.
Barely tested sample below. I couldn't quite figure out if your code was doing what you said it should be doing so I improvised based on your description.
Imports System.Text.RegularExpressions
Public Class Form1
Private Sub ButtonFind_Click(sender As System.Object, e As System.EventArgs) Handles ButtonFind.Click
Dim downloadedString As String
downloadedString = "cookies,dishes,candy," _
& vbNewLine & "back,forward,refresh," _
& vbNewLine & "mail,media,mute,"
'Use the regular expression anchor characters (^$) to match a line that contains the given text.
Dim wordToFind As String = TextBox1.Text & "," 'Include the comma that comes after each word to avoid partial matches.
Dim pattern As String = "^.*" & wordToFind & ".*$"
Dim rx As Regex = New Regex(pattern, RegexOptions.Multiline + RegexOptions.IgnoreCase)
Dim M As Match = rx.Match(downloadedString)
'M will either be Match.Empty (no matching word was found),
'or it will be the matching line.
If M IsNot Match.Empty Then
Dim words() As String = M.Value.Split(","c)
RichTextBox1.Clear()
For Each word As String In words
If Not String.IsNullOrEmpty(word) Then
RichTextBox1.AppendText(word & vbNewLine)
End If
Next
Else
RichTextBox1.Text = "No match found."
End If
End Sub
End Class