How to search for string in an array

Solution 1:

If you want to know if the string is found in the array at all, try this function:

Function IsInArray(stringToBeFound As String, arr As Variant) As Boolean
  IsInArray = (UBound(Filter(arr, stringToBeFound)) > -1)
End Function

As SeanC points out, this must be a 1-D array.

Example:

Sub Test()
  Dim arr As Variant
  arr = Split("abc,def,ghi,jkl", ",")
  Debug.Print IsInArray("ghi", arr)
End Sub

(Below code updated based on comment from HansUp)

If you want the index of the matching element in the array, try this:

Function IsInArray(stringToBeFound As String, arr As Variant) As Long
  Dim i As Long
  ' default return value if value not found in array
  IsInArray = -1

  For i = LBound(arr) To UBound(arr)
    If StrComp(stringToBeFound, arr(i), vbTextCompare) = 0 Then
      IsInArray = i
      Exit For
    End If
  Next i
End Function

This also assumes a 1-D array. Keep in mind LBound and UBound are zero-based so an index of 2 means the third element, not the second.

Example:

Sub Test()
  Dim arr As Variant
  arr = Split("abc,def,ghi,jkl", ",")
  Debug.Print (IsInArray("ghi", arr) > -1)
End Sub

If you have a specific example in mind, please update your question with it, otherwise example code might not apply to your situation.

Solution 2:

Another option would be use a dictionary instead of an array:

Dim oNames As Object
Set oNames = CreateObject("Scripting.Dictionary")
'You could if need be create this automatically from an existing Array
'The 1 is just a dummy value, we just want the names as keys
oNames.Add "JOHN", 1
oNames.Add "BOB", 1
oNames.Add "JAMES", 1
oNames.Add "PHILIP", 1

As this would then get you a one-liner of

oNames.Exists("JOHN")

The advantage a dictionary provides is exact matching over partial matching from Filter. Say if you have the original list of names in an Array, but were looking for "JO" or "PHIL" who were actually two new people in addition to the four we started with. In this case, Filter(oNAMES, "JO") will match "JOHN" which may not be desired. With a dictionary, it won't.

Solution 3:

Another option that enforces exact matching (i.e. no partial matching) would be:

Function IsInArray(stringToBeFound As String, arr As Variant) As Boolean
  IsInArray = Not IsError(Application.Match(stringToBeFound, arr, 0))
End Function

You can read more about the Match method and its arguments at http://msdn.microsoft.com/en-us/library/office/ff835873(v=office.15).aspx

Solution 4:

there is a function that will return an array of all the strings found.

Filter(sourcearray, match[, include[, compare]])
The sourcearray has to be 1 dimensional
The function will return all strings in the array that have the match string in them

Solution 5:

Here's another answer. It works fast, reliably (see atomicules' answer) and has compact calling code:

' Returns true if item is in the array; false otherwise.
Function IsInArray(ar, item$) As Boolean
    Dim delimiter$, list$

    ' Chr(7) is the ASCII 'Bell' Character.
    ' It was chosen for being unlikely to be found in a normal array.
    delimiter = Chr(7)

    ' Create a list string containing all the items in the array separated by the delimiter.
    list = delimiter & Join(ar, delimiter) & delimiter

    IsInArray = InStr(list, delimiter & item & delimiter) > 0
End Function

Sample usage:

Sub test()
    Debug.Print "Is 'A' in the list?", IsInArray(Split("A,B", ","), "A")
End Sub