Android Code Snippet PyIn() - Python 'in'

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wonder

Expert
Licensed User
PyIn() - Find anything in anything!! :)

Replicates the behavior of the Python keyword 'in' which returns true if something is part of something else, meaning that search is possible for:
- characters in strings
- sub-strings in strings
- characters in arrays of characters
- strings of size 1 in arrays of characters
- numbers (double, float, short, int, long) in arrays of numbers (of the same type)
- bytes in arrays of bytes
- objects in arrays of objects
- anything in lists
- anything in maps (as keys)
https://docs.python.org/3/reference/expressions.html (6.10.2. Membership test operations)

Usage:
B4X:
If PyIn(something, someContainer) Then
    'Do Stuff
End If
Snippet:
B4X:
'Returns wheter or not the given object is part of the given container
Sub PyIn(obj As Object, container As Object) As Boolean
    'Is NULL part of NULL? Yes it is!
    '----------------------------------------------------
    If obj == Null And container == Null Then Return True
    '----------------------------------------------------

    'A non-NULL object may not be part of a NULL one
    '----------------------------------------------------
    If container == Null Then Return False
    '----------------------------------------------------

    'Null object workaround
    '----------------------------------------------------
    Dim oType = "java.lang.Object" As String
    If obj <> Null Then oType = GetType(obj)
    '----------------------------------------------------

    'Make sure that object is not an Array
    '----------------------------------------------------
    If oType.CharAt(0) == "[" Then Return False
    '----------------------------------------------------

    Dim cType = GetType(container) As String
    Dim isSearchInArray = cType.CharAt(0) == "[" As Boolean
    oType = oType.SubString(oType.LastIndexOf(".") + 1).CharAt(0)

    If isSearchInArray Then
        Dim cFirstChar = cType.CharAt(1) As Char
        If cFirstChar == "L" Then
            Select cType.CharAt(cType.LastIndexOf(".") + 1)
                Case "S"
                    If oType == "S" Or oType == "C" Then
                        Dim strObj = obj As String
                        Dim strCnt() = container As String
                        For Each str As String In strCnt
                            If str == strObj Then Return True
                        Next
                    End If
                    Return False

                Case "O"
                    If oType == "O" Then
                        Dim objCnt() = container As Object
                        If obj == Null Then
                            For Each o As Object In objCnt
                                If o == Null Then Return True
                            Next
                        Else
                            For Each o As Object In objCnt
                                If o == obj Then Return True
                            Next
                        End If
                    End If
                    Return False

            End Select
            Return False
        End If

        'Allow String in Char() search
        '----------------------------------------------------
        If oType == "S"       _
        And oType.Length == 1 _
        And cFirstChar == "C" Then
            Dim charObj = obj As Char
            Dim charCnt() = container As Char
            For Each c As Char In charCnt
                If c == charObj Then Return True
            Next
            Return False
        End If
        '----------------------------------------------------

        'Make sure that object is the same type as the Array
        '----------------------------------------------------
        If oType == "L" Then oType = "J"
        If oType <> cFirstChar Then Return False
        '----------------------------------------------------

        Select oType
            Case "B"
                Dim byteObj = obj As Byte
                Dim byteCnt() = container As Byte
                For Each b As Byte In byteCnt
                    If b == byteObj Then Return True
                Next

            Case "S"
                Dim shortObj = obj As Short
                Dim shortCnt() = container As Short
                For Each s As Short In shortCnt
                    If s == shortObj Then Return True
                Next

            Case "I"
                Dim intObj = obj As Int
                Dim intCnt() = container As Int
                For Each i As Int In intCnt
                    If i == intObj Then Return True
                Next

            Case "J"
                Dim longObj = obj As Long
                Dim longCnt() = container As Long
                For Each j As Long In longCnt
                    If j == longObj Then Return True
                Next

            Case "F"
                Dim floatObj = obj As Float
                Dim floatCnt() = container As Float
                For Each f As Float In floatCnt
                    If f == floatObj Then Return True
                Next

            Case "D"
                Dim doubleObj = obj As Double
                Dim doubleCnt() = container As Double
                For Each d As Double In doubleCnt
                    If d == doubleObj Then Return True
                Next

            Case "C"
                Dim charObj = obj As Char
                Dim charCnt() = container As Char
                For Each c As Char In charCnt
                    If c == charObj Then Return True
                Next

        End Select
        Return False
    End If

    Select True
        Case container Is String
            Dim strContainer = container As String
            Dim strObj = obj As String
            Return (strContainer.IndexOf(strObj) >= 0)

        Case container Is List
            Dim lst = container As List
            Return (lst.IndexOf(obj) >= 0)

        Case container Is Map
            Dim map = container As Map
            Return map.ContainsKey(obj)

    End Select
    Return False
End Sub
Test Cases:
B4X:
Sub Tests
    'Expected output:
    '    - All tests should return true, meaning the result is as expected.

    'Test String in String()
        Log("01: " & (True  == PyIn("world", Array As String("hello", "world"))))
        Log("02: " & (False == PyIn("world", Array As String("hello", "universe"))))

    'Test Char in Char()
        Dim c As Char = "w"
        Log("03: " & (True  == PyIn(c, Array As Char("h", "w"))))
        Log("04: " & (False == PyIn(c, Array As Char("h", "x"))))

    'Test Char in String()
        Log("05: " & (True  == PyIn(c, Array As String("h", "w"))))
        Log("06: " & (False == PyIn(c, Array As String("h", "x"))))

    'Test String in Char()
        Log("07: " & (True  == PyIn("w", Array As Char("h", "w"))))
        Log("08: " & (False == PyIn("w", Array As Char("h", "x"))))

    'Test Object in Object()
        Dim x As Object
        Dim y As Object
        Dim z As Object = Array As Object(x)
        Log("09: " & (True  == PyIn(x, z)))
        Log("10: " & (False == PyIn(y, z)))

    'Test Byte in Byte()
        Dim b As Byte = 5
        Log("11: " & (True  == PyIn(b, Array As Byte(3, 5))))
        Log("12: " & (False == PyIn(b, Array As Byte(3, 6))))

    'Test Int in Int()
        Dim i As Int = 5
        Log("13: " & (True  == PyIn(i, Array As Int(3, 5))))
        Log("14: " & (False == PyIn(i, Array As Int(3, 6))))

    'Test Float in Float()
        Dim f As Float = 5.0
        Log("15: " & (True  == PyIn(f, Array As Float(3, 5))))
        Log("16: " & (False == PyIn(f, Array As Float(3, 6))))

    'Test Double in Double()
        Dim d As Double = 5.0
        Log("17: " & (True  == PyIn(d, Array As Double(3, 5))))
        Log("18: " & (False == PyIn(d, Array As Double(3, 6))))

    'Test Long in Long()
        Dim j As Long = 5
        Log("19: " & (True  == PyIn(j, Array As Long(3, 5))))
        Log("20: " & (False == PyIn(j, Array As Long(3, 6))))

    'Test Short in Short()
        Dim s As Short = 5
        Log("21: " & (True  == PyIn(s, Array As Short(3, 5))))
        Log("22: " & (False == PyIn(s, Array As Short(3, 6))))

    'Test something in String (incomplete number of test cases)
        Log("23: " & (True  == PyIn(s, "358")))
        Log("24: " & (False == PyIn(s, "378")))

    'Test something in List (incomplete number of test cases)
        Dim lst As List
        lst.Initialize
        lst.Add(x)
        lst.add("5")
        lst.add(5)
        lst.add(b)
        Log("25: " & (True  == PyIn(b, lst)))
        Log("26: " & (False == PyIn(s, lst)))
        lst.add(s)
        Log("27: " & (True  == PyIn(s, lst)))

    'Test something in Map (incomplete number of test cases)
        Dim map As Map
        map.Initialize
        map.Put(j, "long")
        Log("28: " & (True  == PyIn(j, map)))
        Log("29: " & (False == PyIn(d, map)))
        map.Put(d, "double")
        Log("30: " & (True  == PyIn(d, map)))

End Sub
 
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