I am trying write a simple user defined function in Python that I pass a value to from Excel via Xlwings. I ran across some examples with an Add-in that you need to import user defined functions, but that seems overly complex.
Why isn't my example working?
VBA:
Function Hello(name As String) As String
RunPython ("import Test; Test.sayhi(name)")
End Function
Python (Test.py):
from xlwings import Workbook, Range
def sayhi(name):
wb = Workbook.caller()
return 'Hello {}'.format(name)
Error:
NameError: name 'name' is not defined
Make sure you're supplying the argument correctly:
RunPython ("import Test; Test.sayhi('" & name & "')")
The text inside RunPython() should be a valid python script. So the comment from "Tim Williams" is a quick solution. You just need to be careful to avoid ' character inside the name variable to break the python script.
If you need to write UDF (User Defined Function) a lot, or need to pass in value to get the output and then handle the result via VBA, try use ExcelPython instead of Xlwings.
Note, ExcelPython and Xlwings can work together, you can have both without conflict.
I think it's better you play the example to understand the difference. My understanding is limited to my knowledge, which might not be correct.
To summarize the difference:
ExcelPython needs a installer to be installed, it is good in UDF, which helps if you want to pass arguments in and out, and the function is cached in memory, so later call will be very quick.
Xlwings is simpler by just add the VBA module, no installer needed. It trigger Python in the background each time to run the script (each call starts a new process), in the script you can manipulate (read/write) Excel via COM.
I have the same question in the beginning, but later I find out using VBA in Excel side (intellisense) plus ExcelPython on UDF (simply process and return the data back) is a nice combination, so I think ExcelPython is only what I need.
As mentioned earlier, the 2 components have no conflict, you can have both. If the 2 author agree too, it is a good idea to combine them.
Related
When I run the code below, I get different results when I run in .py compared to when I run in .exe using pyinstaller
import win32com.client
import os
ConfigMacroName = "test.xls"
xl=win32com.client.Dispatch("Excel.Application")
Configmacrowb = xl.Workbooks.Open(os.getcwd()+ "\\Completed\\" + ConfigMacroName)
SlotPlansheet = Configmacrowb.Sheets("SlotPlan")
Header = SlotPlansheet.Rows(1)
SOcol = Header.Find('SO', LookAt=1).Column #I used LookAt=1 which is equivalent to LookAt:=xlWhole in excel VBA
SOlinecol = Header.Find('SO Line').Column
print("SO is " + str(SOcol) + "\nSo line is " + str(SOlinecol))
SlotPlansheet = None
Configmacrowb.Close(False)
Configmacrowb = None
xl.Quit()
xl = None
The excel input
The output in .py
The output in .exe
The output in .py file is the correct output I need. If I run it in .exe there will be duplicate variable since they both will refer to column B. For temporary solution I can just loop through the header to check each cell.
But I'm using find() function a lot so I don't know if my other programs are also affected by this inconsistency
Try changing the object creation line to:
xl=win32com.client.gencache.EnsureDispatch(‘Excel.Application’)
In my experience, the win32com.client.Dispatch() function can sometimes cause issues in that it does not guarantee the same result every time it runs. The caller doesn't know if they have an early- or late-bound object. If you have no cached makepy files then you will get a late-bound IDispatch automation interface, but if win32com finds an early-bound interface then it will use it (even if it wasn't your programme that created it). Hence code that ran fine previously may stop working.
Unless you have a good reason to be indifferent, I think it is better to be explicit and choose win32com.client.gencache.EnsureDispatch() or win32com.client.dynamic.Dispatch() for early- or late-binding respectively. I generally choose the EnsureDispatch() route, as it is quicker, enforces case-sensitivity, and gives access to any constants in the type library (eg win32com.client.constants.xlWhole) rather than rely on 'magic' integers.
Also, in the past, I have experienced odd behaviour around indexing (eg this SO question), and this was cured by deleted any gencache wrappers (see below).
Add this line to your debug code:
print('Cache directory:',win32com.client.gencache.GetGeneratePath())
This will tell you where the gencache early-binding python files are being generated, and where win32com.client.Dispatch() will look for any cached wrapper files to attempt early-binding. If you want to clear the cached of generated files just delete the contents of this directory. It will be interesting to see if the OP's two routes have the same directory.
I'm trying to learn how to use variables from Jenkins in Python scripts. I've already learned that I need to call the variables, but I'm not sure how to implement them in the case of using os.path.join().
I'm not a developer; I'm a technical writer. This code was written by somebody else. I'm just trying to adapt the Jenkins scripts so they are parameterized so we don't have to modify the Python scripts for every release.
I'm using inline Jenkins python scripts inside a Jenkins job. The Jenkins string parameters are "BranchID" and "BranchIDShort". I've looked through many questions that talk about how you have to establish the variables in the Python script, but with the case of os.path.join(),I'm not sure what to do.
Here is the original code. I added the part where we establish the variables from the Jenkins parameters, but I don't know how to use them in the os.path.join() function.
# Delete previous builds.
import os
import shutil
BranchID = os.getenv("BranchID")
BranchIDshort = os.getenv("BranchIDshort")
print "Delete any output from a previous build."
if os.path.exists(os.path.join("C:\\Doc192CS", "Output")):
shutil.rmtree(os.path.join("C:\\Doc192CS", "Output"))
I expect output like: c:\Doc192CS\Output
I am afraid that if I do the following code:
if os.path.exists(os.path.join("C:\\Doc",BranchIDshort,"CS", "Output")):
shutil.rmtree(os.path.join("C:\\Doc",BranchIDshort,"CS", "Output"))
I'll get: c:\Doc\192\CS\Output.
Is there a way to use the BranchIDshort variable in this context to get the output c:\Doc192CS\Output?
User #Adonis gave the correct solution as a comment. Here is what he said:
Indeed you're right. What you would want to do is rather:
os.path.exists(os.path.join("C:\\","Doc{}CS".format(BranchIDshort),"Output"))
(in short use a format string for the 2nd argument)
So the complete corrected code is:
import os
import shutil
BranchID = os.getenv("BranchID")
BranchIDshort = os.getenv("BranchIDshort")
print "Delete any output from a previous build."
if os.path.exists(os.path.join("C:\\Doc{}CS".format(BranchIDshort), "Output")):
shutil.rmtree(os.path.join("C:\\Doc{}CS".format(BranchIDshort), "Output"))
Thank you, #Adonis!
Can anyone give me an idea about how to call Matlab function from python script using pymatlab?
Matlab, pymatlab and python are already properly installed.
I tried to run some Matlab commands from here on python script and everything works fine. But I have no idea regarding calling Matlab function from python.
For example, I have a Matlab function which will receive a string as argument and will display it and return it, like below.
function [ name ] = print_Name(first_Name)
name=first_Name;
end
Thanks in advance for your kind suggestion.
You need to first initialize a MATLAB session
import pymatlab
session = pymatlab.session_factory()
Then you can use the run method to call any MATLAB function that you wish
session.run("print_Name('name')")
Or you could assign a value in the workspace and use that
name = 'My Name'
session.putValue('name', name)
session.run('print_Name(name)')
If you want to get a value back, you can always assign the output of print_Name to a variable and call session.getValue to get that back into Python
session.run('output = print_Name(name)')
result = session.getValue('output')
That being said, I would highly recommend using The Mathwork's own library for interacting with MATLAB from Python.
So I have discovered the python extension for SPSS, and everything works fine, I have created some scripts now and included them in the extensions map and it works fine. However, now I have created a couple of scripts that require arguments, I thought I could just follow the same method but I guess not.
def Run(args):
import spss
def testing_p(variables):
all_variables = [spss.GetVariableName(i) for i in range(spss.GetVariableCount())]
variable_nr = [all_variables.index(i) for i in variables]
print all_variables
print variable_nr
With the following .xml-file:
<Command xmlns="http://xml.spss.com/extension" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" Name="testing_p" Language="Python">
</Command>
However, this keep throwing the error when calling testing_p(['my_var', 'my_var2']):
Warnings
This command should specify a valid subcommand at the beginning.
Execution of this command stops.
I cannot wrap my head around this because everything works fine when not put in the extensions map and only doing:
BEGIN PROGRAM.
import spss
def testing_p(variables):
all_variables = [spss.GetVariableName(i) for i in range(spss.GetVariableCount())]
variable_nr = [all_variables.index(i) for i in variables]
print all_variables
print variable_nr
END PROGRAM.
For an extension, which can be writen in Python, R, or Java, you need to create a syntax specification containing the command name, any subcommands, and the arguments and argument types you want. Here is a picture of the start of one (SPSSINC_TURF, which is installed with Statistics).
This will guide the Statistics parser in checking the user input. It also then calls the Run function with a complicated structure containing the user input. You can use the functions in the extensions module to map that to your Python variables and do further validation. Here is a picture of the start of the Run function for SPSSINC TURF.
Finally, if the syntax is valid, your Run function calls the worker function to do something useful, mapping all the parameters to the specified arguments by calling
processcmd(oobj, args, superturf, vardict=spssaux.VariableDict())
which was imported from extensions.py.
Look at the doc for extensions in the help system, and look at some of the extensions installed with Statistics for examples.
Finally, here is a slide from one of my presentations summarizing the flow from user input to results.
Please excuse what I know is an incredibly basic question that I have nevertheless been unable to resolve on my own.
I'm trying to switch over my data analysis from Matlab to Python, and I'm struggling with something very basic: in Matlab, I write a function in the editor, and to use that function I simply call it from the command line, or within other functions. The function that I compose in the matlab editor is given a name at the function definition line, and it's generally best for the function name to match the .m file name to avoid confusion.
I don't understand how functions differ in Python, because I have not been successful translating the same approach there.
For instance, if I write a function in the Python editor (I'm using Python 2.7 and Spyder), simply saving the .py file and calling it by its name from the Python terminal does not work. I get a "function not defined" error. However, if I execute the function within Spyder's editor (using the "run file" button), not only does the code execute properly, from that point on the function is also call-able directly from the terminal.
So...what am I doing wrong? I fully appreciate that using Python isn't going to be identical to Matlab in every way, but it seems that what I'm trying to do isn't unreasonable. I simply want to be able to write functions and call them from the python command line, without having to run each and every one through the editor first. I'm sure my mistake here must be very simple, yet doing quite a lot of reading online hasn't led me to an answer.
Thanks for any information!
If you want to use functions defined in a particular file in Python you need to "import" that file first. This is similar to running the code in that file. Matlab doesn't require you to do this because it searches for files with a matching name and automagically reads in the code for you.
For example,
myFunction.py is a file containing
def myAdd(a, b):
return a + b
In order to access this function from the Python command line or another file I would type
from myFunction import myAdd
And then during this session I can type
myAdd(1, 2)
There are a couple of ways of using import, see here.
You need to a check for __main__ to your python script
def myFunction():
pass
if __name__ == "__main__":
myFunction()
then you can run your script from terminal like this
python myscript.py
Also if your function is in another file you need to import it
from myFunctions import myFunction
myFunction()
Python doesn't have MATLAB's "one function per file" limitation. You can have as many functions as you want in a given file, and all of them can be accessed from the command line or from other functions.
Python also doesn't follow MATLAB's practice of always automatically making every function it can find usable all the time, which tends to lead to function name collisions (two functions with the same name).
Instead, Python uses the concept of a "module". A module is just a file (your .py file). That file can have zero or more functions, zero or more variables, and zero or more classes. When you want to use something from that file, you just import it.
So say you have a file 'mystuff.py':
X = 1
Y = 2
def myfunc1(a, b):
do_something
def myfunc2(c, d):
do_something
And you want to use it, you can just type import mystuff. You can then access any of the variables or functions in mystuff. To call myfunc2, you can just do mystuff.myfunc2(z, w).
What basically happens is that when you type import mystuff, it just executes the code in the file, and makes all the variables that result available from mystuff.<varname>, where <varname> is the name of the variable. Unlike in MATLAB, Python functions are treated like any other variable, so they can be accessed just like any other variable. The same is true with classes.
There are other ways to import, too, such as from mystuff import myfunc.
You run python programs by running them with
python program.py