checking string for all blanks

[Jeff]

Could someone tell me the easiest way to check a string of variable length
to see if it consists of all blank characters?

....or perhaps more generally, to see if all of the characters are the same.


Thanks

Jeff


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[Johnny Jörgensen]

Re: checking string for all blanks

If MyString.Trim = "" Then
....
End If

Cheers,
Johnny J.




"Jeff" <none@nothingX. comwrote in message
news:4642a23e$0 $1468$88260bb3@ free.teranews.c om...

>
Could someone tell me the easiest way to check a string of variable length
to see if it consists of all blank characters?
>
...or perhaps more generally, to see if all of the characters are the
same.
>
>
Thanks
>
Jeff
>
>
--
Posted via a free Usenet account from http://www.teranews.com
>

[Andrew Morton]

Re: checking string for all blanks

Jeff wrote:

Could someone tell me the easiest way to check a string of variable
length to see if it consists of all blank characters?

Assuming an empty string counts as all blank chars,

If Len(Trim(someSt ring))=0 then...

...or perhaps more generally, to see if all of the characters are the
same.

If Len(someString) >0 AndAlso Len(someString. Trim(someString .Chars(1))) = 0
Then...

Andrew

[=?ISO-8859-1?Q?G=F6ran_Andersson?=]

Re: checking string for all blanks

Jeff wrote:

>
Could someone tell me the easiest way to check a string of variable
length to see if it consists of all blank characters?
>
...or perhaps more generally, to see if all of the characters are the same.

The most resource effecive and scalable would be to just loop the string:

Function IsAllSameCharac ter(s As String)
Dim first As Char = s.Chars(0)
ForEach c As Char in s
If c <first Return False
Next
Return True
End Function

[Disclaimer: Code is not tested]

--
Göran Andersson
_____

http://www.guffa.com

[Jeff]

Re: checking string for all blanks


"Göran Andersson" <guffa@guffa.co mwrote in message
news:uJlusPwkHH A.4312@TK2MSFTN GP02.phx.gbl...

Jeff wrote:

The most resource effecive and scalable would be to just loop the string:
>
Function IsAllSameCharac ter(s As String)
Dim first As Char = s.Chars(0)
ForEach c As Char in s
If c <first Return False
Next
Return True
End Function
>
[Disclaimer: Code is not tested]

Other than a typo involving a missing space and one other, it ran fine.
Thanks - my tested code is below. I don't know enough to determine whether
this is the most resource effective relative to the other alternatives
provided, but I will take your word for it. Jeff

Function IsAllSameCharac ter(ByVal s As String)
Dim first As Char = s.Chars(0)
For Each c As Char In s
If c <first Then
Return False
End If
Next
Return True
End Function



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[Stephany Young]

Re: checking string for all blanks

Take his word for it that it is certainly resource effective and scalable.

Whether it is the most ... is a matter of debate.

For short strings it will be lightening fast.

For longer strings, the further it has to loop through the characters the
longer it will take and you might find it quicker to do something like:

Function IsAllSameCharac ter(ByVal s As String)

Dim _s As String = New String(s.Chars( 0), s.Length)

Return (s = _s)

End Function



"Jeff" <none@nothingX. comwrote in message
news:4643b29b$0 $13538$88260bb3 @free.teranews. com...

>
"Göran Andersson" <guffa@guffa.co mwrote in message
news:uJlusPwkHH A.4312@TK2MSFTN GP02.phx.gbl...

>Jeff wrote:

>

>The most resource effecive and scalable would be to just loop the string:
>>
>Function IsAllSameCharac ter(s As String)
> Dim first As Char = s.Chars(0)
> ForEach c As Char in s
> If c <first Return False
> Next
> Return True
>End Function
>>
>[Disclaimer: Code is not tested]

>
Other than a typo involving a missing space and one other, it ran fine.
Thanks - my tested code is below. I don't know enough to determine whether
this is the most resource effective relative to the other alternatives
provided, but I will take your word for it. Jeff
>
Function IsAllSameCharac ter(ByVal s As String)
Dim first As Char = s.Chars(0)
For Each c As Char In s
If c <first Then
Return False
End If
Next
Return True
End Function
>
>
>
--
Posted via a free Usenet account from http://www.teranews.com
>

[=?ISO-8859-1?Q?G=F6ran_Andersson?=]

Re: checking string for all blanks

Stephany Young wrote:

Take his word for it that it is certainly resource effective and scalable.
>
Whether it is the most ... is a matter of debate.
>
For short strings it will be lightening fast.

Yes, but that is not very interresting. For short strings it doesn't
really matter. It's what happens when the strings get larger that
matters for scalability.

For longer strings, the further it has to loop through the characters
the longer it will take and you might find it quicker to do something like:
>
Function IsAllSameCharac ter(ByVal s As String)
>
Dim _s As String = New String(s.Chars( 0), s.Length)
>
Return (s = _s)
>
End Function
>

But that will make two loops instead of one. First it will do a loop to
initialise the new string, then it will do another loop to compare all
the characters between the strings. At best (when all characters are the
same) it's half as fast, at worst (when the first two characters differ)
it's much slower, as the first loop will always loop through all the
characters regardless if they are used or not.

As this method creates another string that is as large as the original
string, it does not scale well. The method that I presented only
allocates memory for a repeater, and that is the same regardless of the
size of the string.

--
Göran Andersson
_____

http://www.guffa.com