Question about dictionaries

Getting Started
1

Why do I get an exception for this:

[code] Dim tmp_string() as String = Split(“F1,F2,F3,F4,F5,F6,F7,F8,F9,F10”, “,”)

dim mydict as Dictionary

dim zz as Integer
for zz=0 to ubound(tmp_string)
dim astring as string
astring = tmp_string(zz)
mydict.value(astring)=zz // Why an exception here???
Listbox1.AddRow(tmp_string(zz))
dim bstring as string
bstring = hex(mydict.Value(astring))
Listbox1.AddRow(bstring)
next[/code]

2

Try:

dim mydict as new Dictionary
3

Are these the results you are after?

4

What are you trying to accomplish? Converting F1, F2 etc. to Hex?

5

To clarify Mike’s answer (after he seems to have gone the extra mile — nice job!), you must create an instance of a class before you can use it. dim mydict as Dictionary just says, “mydict will hold a dictionary,” but it starts as nil. The shorthand dim mydict as new Dictionary is the same as:

dim mydict as Dictionary
mydict = new Dictionary
6

Glenn I figured you are trying to convert your Fx characters to Hex or Ascii. I wrote this to test your original post.

I wasn’t sure why you were looking for the dictionary so I removed it trying to guess :slight_smile:

Note: This breaks when you go past F9 as I didn’t break the characters down into a Memory Block to convert them to ascii/hex (properly) :). Was this the path you were looking at?

HTH.

  Dim tmp_string() as String = Split("F1,F2,F3,F4,F5,F6,F7,F8,F9", ",")
  Dim String1, String2, String1ToASC, String2ToASC as String
  for zz as Integer =0 to ubound(tmp_string)
    String1 = tmp_string(zz).mid(1,1)
    String2 = tmp_string(zz).Mid(2,1)
    String1ToASC = Str(Asc(String1))
    String2ToASC = Str(Asc(String2))
    Listbox1.AddRow(tmp_string(zz)+ "      ASCII ("+String1ToASC + ","+ String2ToASC+")"+ "    HEX ("+hex(String1ToASC) + ","+ hex(String2ToASC)+")")
  next zz
7

My example was bizzar I will admit.

I want to create a lookup table that goes both way. The array of strings allows me to put in an integer and back a string. Then the dictionary was to allow me to put in a string and get back a number

8

Can you give an example of each direction? Are you looking for a String to convert to a Ascii or hex value? A correlation example would help. Thanks!

9

Array.indexof will give you the integer value of the position of the string.

Dim i As Integer = tmp_string.IndexOf(“F10”)

should give 9 as the result.

Please note I’m doing this off-line, so some adjustments may be necessary.

10

Awesome Wayne :slight_smile: Since you are offline here is a link to then Xojo Docs for Indexof. It has a great example relevant to Glenn’s post.

Xojo IndexOf Doc

11

You might check out my “two-way dictionary” article in xDev 9.5 (Article 9509: : A Two-Way Dictionary) – the download is free though you have to buy the issue to read the article.

The advantage of a dictionary versus an array is speed, which is only important if you have a large dataset you want to do this with.

12

The indexof was exactly what I was looking for. Thank you