Android Question Getting a piece of a text string using a delimiter

[Colin Evans]

Hi, I need to be able to extract a piece if text between two delimiters, i.e. if the 'text' string is something like '/this is one/this is two/this is three/this is four' I need to be able to define the delimiter as '/' and then have the code extract a piece of the data.

In VB6 I'd create a Function

Function Piece(sSource As String, sDelimiter As String, iPiece As Integer)
Dim s As String
s = sSource + sDelimiter
Dim i As Integer
Dim iDelPos As Integer
If iPiece > 1 Then
For i = 1 To iPiece - 1
iDelPos = InStr(s, sDelimiter)
s = Mid(s, iDelPos + 1, Len(s))
Next i
End If
If s = "" Then
Piece = ""
Else
Piece = Mid(s, 1, InStr(s, sDelimiter) - 1)
End If
End Function

And then to extract say the third piece of data from the I'd simply execute the following

dim TextExtract as string
TextExtract = Piece(text, "/",3)

and TextExtract would = 'this is three'

is this possible in B4A

 

[LucaMs]

Regex.Split

https://www.b4x.com/android/help/regularexpressions.html#regex_split

 

[Colin Evans]

How would that work relating to my example where I want to extract a particular piece of the data, where I can then use TextExtract elsewhere.

basically the text I am wanting to extract from contains a path to a filename

//rootfiledir/examples/exampleD/file123.png

and I just want the filename 'file123.png' as it isn't in the path given but is in my files

so I just want to be able to load it with

LoadBitmap(File.DirAssets,TextExtract)

Hope that makes sense, thanks for replying

 

[Sandman]

How would that work relating to my example

I'm not sure I understand where the problem is. LucaMs is absolutely correct, Split is the solution to use. Did you read the linked docs? In it we have this example:

Dim components() As String 
components = Regex.Split(",", "abc,def,,ghi") 'returns: "abc", "def", "", "ghi"

Just do that and pick the last item of the array and you'll have the filename.

 

[Mahares]

so I just want to be able to load it with
LoadBitmap(File.DirAssets,TextExtract)

Here is the snippet that pertains to your case:

Dim strVar As String="//rootfiledir/examples/exampleD/file123.png"
    Dim strArray() As String=Regex.Split("/",strVar)
    Dim TextExtract As String=strArray(strArray.Length-1)  'last item which is:  file123.png
Activity.SetBackgroundImage(LoadBitmap(File.DirAssets,TextExtract))

 

[Colin Evans]

Many thanks, think its just getting my head around different ways of working

 

[LucaMs]

Here is the snippet that pertains to your case:

Dim strVar As String="//rootfiledir/examples/exampleD/file123.png"
    Dim strArray() As String=Regex.Split("/",strVar)
    Dim TextExtract As String=strArray(strArray.Length-1)  'last item which is:  file123.png
Activity.SetBackgroundImage(LoadBitmap(File.DirAssets,TextExtract))

In that specific case you can use:

    Dim strVar As String = "//rootfiledir/examples/exampleD/file123.png"
Dim TextExtract As String = strVar.SubString(strVar.LastIndexOf("/") + 1)

 

[Colin Evans]

Hi just a quick question, the date returned in the JSON data is in the format of YYYY-MM-DD i.e 2018-05-28 is there a quick way to change this to DD/MM/YYYY i.e. 28/05/2018 so its displayed this way

 

[DonManfred]

remember the Dateformat
Set the dateformat to match you datestr
Parse the datestr to a date (LONG)
set dateformat to match your expected output
use the date value to output
set dateformat to the remembered value

 

[Colin Evans]

Sorry tried but I can't seem to get it right, basically don't know what to do

                    Dim date0 As String = col0.Get("date")
                    DateTime.DateFormat = "yyyy-mm-dd"
                    DateTime.DateParse(date0)
                    DateTime.DateFormat="dd/mm/yyyy"
                    btnDay1.Text = date0

still puts 2018-05-28 in btnDay1.text

 

[MarkusR]

you forgot that DateTime.DateParse(date0) have a return value

 

[Colin Evans]

Dim date0 As String = col0.Get("date")
                    DateTime.DateFormat = "yyyy-mm-dd"
                    Dim lngDate As Long= DateTime.DateParse(date0)
                    DateTime.DateFormat="dd/mm/yyyy"
                    btnDay1.Text = lngDate

This doesn't work either, gives me a long numeric value as the date, sorry to be a pain, I basically have seven dates returned by the JSON data and I simply want to get the Day of the week name for each date, but that function requires the date to be in a specific format as you know

 

[LucaMs]

Dim date0 As String = col0.Get("date")
                    DateTime.DateFormat = "yyyy-mm-dd"
                    Dim lngDate As Long= DateTime.DateParse(date0)
                    DateTime.DateFormat="dd/mm/yyyy"
                    btnDay1.Text = lngDate

btnDay1.Text = DateTime.Date(lngDate)

 

[Colin Evans]

Amazing, many thanks, and then top get the day of the week name would it be

lblDOW1.Text=DateUtils.GetDayOfWeekName(lngDate)

Yes it does but had to change the date format to MM/dd/yyyy, many thanks for all your help