Passing parameters to Python script with Shell.Execute

Same here.

Same here.

If Python got a decent compiler and IDE it would wipe the floor with anything else …

How about using an [in-memory?] database and doing a LIKE search instead?

Once upon a time I felt the lure of Python, too. So many many nice codes. Alas, Xojo as language is 1000% better than Python.

  1. whitespace (majorly awful)
  2. case sensitive (are they nuts?)
  3. multiple returns from a function

The latter one broke me as I never could be sure what a function would return. Commercial code had to make sure that everything was in place - stuff that in Xojo the compiler enforces.

For a private project: more fun to you.

Oh, the IDE I used - PyCharm - was pretty nifty. Way too small buttons. But really nice to use. Actually working auto-complete. Debugger values shown inline with the code - that was great.

P.S. That would also be VERY slow in my opinion …

I just used Levenshtein distance as an example. I did implement what I needed in yet another language, and it was extremely slow and I had to “translate it” into that language from whatever I could find on the web and debug the code etc. I am happier if I can find a pre-baked solution.

I have not used the Python implementation so I have no first hand experience. But my impression is that the Python implementation is done as a call to complied C code which was written by professionals to be fast and efficient. Once I get my Xojo/Python linkage project worked out, I will try it.

As for the slowness, it was very slow but I used various “cheats” like filtering out cases that neither the first letter of the last or first names matched and in this way made it more manageable.

You may already know of this but thought I’d mention that Joe Strout has a String Utils module on his website that calculates Levenshtein distance along with loads of other functions.

[quote=391565:@Robert Livingston]My biggest problem in Python is not being able to create applications with nice GUI interfaces which I can do in Xojo.[/quote]wxPython uses the native widgets of each supported platform.

For an IDE you could look at Visual Studio Code

I think Einhugur offer some classes to enable interaction between Xojo and Python.

wxPython is a cross-platform GUI toolkit for the Python programming language. It allows Python programmers to create programs with a robust, highly functional graphical user interface, simply and easily.

While I am very glad that wxPython and the Phoenix variant exist, when compared with using Xojo, these are a long way from easy IMO.

I have just started working with my daughter on a QGIS project. QGIS Amazing free resource if you are into cartography. But it is one of those things that is married to Python. I would like, in my own life, to get the best of Xojo and Python. So I could do something like working with Xojo linked with Python to do QGIS stuff.

I will say no more until I have actually done something interesting. Talk/speculation is cheap.

And I have hijacked my own thread. :frowning:

The problem originally described was one of reliably passing data in the form of string(s) to a Python script using Shell.Execute. There is the related issue of getting data back from that same Python script using Shell.Result.

[code]Const SPACE = " "
Const PATH_PYTHON3 = “/Users/owl/anaconda3/bin/python”
Const PATH_PYTHON_SCRIPT = “/Users/owl/Documents/PythonPractice/PythonLittleApps/”

Dim argument1 As String
argument1 = “abcde”
Dim argument2 As String
argument2 = “pqrst”

Dim pyShell As New Shell
pyShell.Execute(PATH_PYTHON3 + SPACE + PATH_PYTHON_SCRIPT + SPACE + argument1 + SPACE + argument2)

Dim sResult As String
sResult = pyShell.Result
One difficulty is passing certain characters that are misinterpreted when they go to the Shell. Characters like $; !; < etc.

If you need to pass such characters, one can figure out what all these characters are and escape them before sending them to the Shell

Tim Jones basically contributed:

[code]Const METHOD_NAME As Text = “FixSpecial”
Const CHARACTERS_THAT_MUST_BE_ESCAPED As String = “\ ` ~ ! @ # $ % ^ & * ( ) | { } [ ] ’ ; < > ? “””
For Each iChar As String In Split(CHARACTERS_THAT_MUST_BE_ESCAPED, " ") // It is split on space.
sEscaped = sEscaped.ReplaceAll(iChar, “” + iChar) // each trouble character gets replaced with escaped version

sEscaped = sEscaped.ReplaceAll(" ", "\ ") // spaces get escaped

Return sEscaped[/code]

Markus Winter noted that if you enclose the arguments in quotes most of the troublesome characters do not need to be escaped although a few still do and based on this:

[code]Const METHOD_NAME As Text = “EscapedArgument”
Const SQ = &u27 // ’ Single Quote
Const DQ = &u22 // " Double Quote

Dim backslashAndDollarSign As String = “” + “$”
Dim backslashAndBacktick As String = “” + “`”
Dim backslashAndSingleQuote As String = “” + SQ
Dim backslashAndDoubleQuote As String = “” + DQ

arg = ReplaceAll(arg, “`”, backslashAndBacktick)
arg = ReplaceAll(arg, “$”, backslashAndDollarSign)
arg = ReplaceAll(arg, SQ, backslashAndSingleQuote)
arg = ReplaceAll(arg, DQ, backslashAndDoubleQuote)

arg = DQ + arg + DQ

Return arg[/code]

Either of these formulation work equally well as best I can tell. Just run the arguments through one or the other of these functions before passing them to pyShell.Execute

pyShell.Execute(PATH_PYTHON3 + SPACE + PATH_PYTHON_SCRIPT + SPACE + FixSpecial(argument1) + SPACE + EscapedArgument(argument2))

The script might be:

[code]import sys
def main():

sReverseArg1 = PassedArg1[::-1]


This suffices for when you want to accept and send back simple ASCII text.

The next problem was sending and receiving back non-Ascii characters should you need to do that. Characters like . Basically, the above does not work.

It turns out that easiest solution really lies on the Python side of things.

If you want to deal with Non-Ascii characters either when you receive them or send them back from Python when called from the Shell.Execute, try adding the codec “stuff” to the PYTHON_SCRIPT code

[code]import sys
def main():

import codecs
sys.stdout = codecs.getwriter("utf-8")(sys.stdout.detach())

sReverseArg1 = PassedArg1[::-1]


And then it works.

P.S. Beatrix suggested the possibility of using BASE64 encoding to traverse the gap from Xojo to Python and then Python back to Xojo.

BASE64 encoding represents the text in characters that are all part of the ASCII set and which contain none of the troublesome characters like $ and <. This methodology can also deal with non-ASCII characters because they get coded as BASE64 characters that are all ASCII.

I submit this here just in case some situation arises that this approach is preferable. I did get it to work although not very elegant.

[code]Const SPACE = " "
Const PATH_PYTHON3 = “/Users/owl/anaconda3/bin/python”
Const PATH_PYTHON_SCRIPT = “/Users/owl/Documents/PythonPractice/PythonLittleApps/”

Dim argument1 As String
argument1 = “abcde”
Dim argument2 As String
argument2 = “pqrst”

Dim pyShell As New Shell
pyShell.Execute(PATH_PYTHON3 + SPACE + PATH_PYTHON_SCRIPT + SPACE + EncodeBase64(argument1, NO_LINE_BREAK) + SPACE + EncodeBase64(argument1, NO_LINE_BREAK))

Dim sResult As String
sResult = DecodeBase64(pyShell.Result, Encodings.UTF8)

On the Python side of things, you do not have to use codec “stuff” because relying on BASE64 encoding and decoding.

[code]import sys
def main():
import os
import base64
# decode to get the string that was passed
incomingBase64Arg1 = sys.argv[1] # gets the Base64 from Xojo
bDecodedArg1 = base64.b64decode(incomingBase64Arg1) # get the binary string
utf8DecodedArg1 = bDecodedArg1.decode(‘utf-8’) # convert to a utf8 string

# do something in Python (reverse for example)
sReverseArg1 = utf8DecodedArg1[::-1]#+"<CR>"#+"\


# code in preparation for sending it out from Python to Xojo

# Put in output buffer


I apologize for any typo’s or stupid things that may exist in the code samples.

The Tkinter occam that ties the TCL/TK UI components into Python is your best option for truly cross platform support - every Unix, Mac OS, and Windows supports it. You could always look into PAGE for building a Tkinter GUI for Python use. While not as directly tied in like JavaFX Scene Builder or Xojo, it’s still pretty good at giving you what you need (and enforcing a MVC model design).

PAGE Editor on Sourceforge

Thanks. But my intent is to use Xojo for lots of the coding work and not only the GUI. So I can use Python if I need it to crack part of a problem and Xojo to crack other parts. And make the GUI in Xojo.
Fortunately, since this is all for myself, I do not have to worry about dual platform.
But dual platform is certainly interesting in that Xojo CAN do it but injects a little more complexity with edge stuff.
Meanwhile, I will look at some of these Python GUI builders. But I do not see one that everybody says this is great and easy.

I provided some sample code above and below is a little snippet from that submission.

passedArg1=sys.argv[1] passedArg2=sys.argv[2] sReverseArg1 = PassedArg1[::-1] print(sReverseArg1) print(passedArg2)

Python is case-sensitive so there is a bug here. The capital “P” in PassedArg1[::-1] is wrong. It should be passedArg1[::-1]

sReverseArg1 = passedArg1[::-1]

Just in case some tries copying and pasting this code and gets an error message as I did today.

Did you check out the python plugins of Björn?

Thanks for the heads up. I haven’t, and I should look at the demo.
But I am a non-commercial, hobbyist programer and avoid plugins for this reason.
I like Python and am curious about it. And I wonder just how much I can do with just using what is built in to Xojo. My “experiments” are early, but intriguing. My interests focus around:

  1. Using Xojo as a GUI for Python
  2. Using Python to accomplish certain tasks that are not easy to do in Xojo. So in this scenario, Python is acting as a silent supplement to Xojo.
    The key to doing this is figuring out how to pass data back and forth between the two environments. As my use expands, I find myself writing little reusable bits of code in Python and Xojo to make it easier to communicate between the two. I do not know how far this will go. It is a typical hobbyist project with a taint of tilting at windmills. But I have one solid “working” solution to another wise annoying problem which was enabled by marrying Xojo with Python.
    I wonder if Xojo itself could embrace being a GUI for Python. There is a need for Python to have a reasonable GUI tool. What they have to date, doesn’t seem to me to be very inspiring.

I don’t think there’s much mileage in using Xojo for that, Python has plenty of high quality options for creating a GUI:

wxPython (Native)
Qt for Python (Qt)
PyGObject (GTK)
Kivy (Kivy)
PySciter (Sciter)
IronPython (.NET)

Thanks for this list and I should look into these more. But just the fact that there are 6 choices makes me think that none of them can be that great.
And to my knowledge, all of these are specifying the GUI in code. In these Python GUI creation tools, you are writing out code to specify the size and location of a Button for example. I remember doing this type of programming in the 1990’s using Foxbase. And I am not eager to return to that methodology.
In Xojo, if you want a Button of such and such size in a location, you place there in the IDE and size it in the IDE without writing actual code. Xojo takes care of it. It is a far different experience.
The fact that I can write a Python program with a GUI using these listed tools is fine. But for me, not attractive.

Follow my link to PAGE above. It is a GUI layout editor. Also, take a look at the “Getting Started” doc.

Many of us older REALbasic users will recognize the designer layout :).

There are six different modules because they are for six different GUI toolkits. I’ve only listed the ones that are great, I could have included PyFLTK, TKinter and others but they’re not so good (imo).

wxPython is the one most similar to Xojo in that it uses the platform’s native widgets.

That’s optional. wxPython, Qt for Python, PyGObject and ironPython all have drag and drop visual designers.