Why Does Replace Return Nothing on Empty String

Question

Replace("",vbLf, "")

Go figure.

It should return ""

No. It returns nothing.

Just put the code in vb.net

I think it should return "". Replace all occurance of vbLF with "". Because the original string is "" then it simply replace nothing and we got back ""

\No. We got back nothing.

Could you re-write your question using sentences with verbs and a question mark to indicate what question you'd like answered? This is unclear. — sarnold, Feb 28 '12 at 02:57

score 3 · Accepted Answer · answered Feb 28 '12 at 03:08

3

You are using Visual Basic string functions, not .Net. The Visual Basic runtime usually evaluates Nothing as an empty string ("").

answered Feb 28 '12 at 03:08

Kenneth Funk

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hmm... let me check string.replace instead – user4951 Mar 01 '12 at 04:00
"evaluates" should be "equates" – Mark Hurd Jul 07 '12 at 18:41

score 1 · Answer 2 · answered Nov 27 '13 at 07:12

1

I second the original post, VB.net should not return NOTHING with its REPLACE function. However, it does if your replace happens to return Nothing if the expression is an empty string.

answered Nov 27 '13 at 07:12

AdamL

177
3
5

Jacob M. · Answer 3 · 2022-11-04T14:16:08.963

To elaborate on this for anyone winding up here, when you just call "Replace" you're getting Microsoft.VisualBasic.Replace, not the String.Replace you're expecting.

Microsoft.VisualBasic.Replace: https://learn.microsoft.com/en-us/dotnet/api/microsoft.visualbasic?view=netframework-4.7.2

String.Replace: https://learn.microsoft.com/en-us/dotnet/api/system.string.replace?view=netframework-4.7.2

If you want to return an empty string you need to call the .Replace method of a String:

dim myString as String = ""
myString.Replace("a", "b")

This of course finds no match, but the behavior is instead to return and empty string now instead of Nothing when the input expression is an empty String.

Why Does Replace Return Nothing on Empty String

3 Answers3