topic Re: reusing a codeblock? in Python Questions

reusing a codeblock?

KeithD1 — Fri, 23 Sep 2016 19:55:34 GMT

I'm using arcpy.CalculateField_management() with a large-ish codeblock. Is there a way to store the codeblock so it can be easily reused multiple times, and more importantly, easily edited? This is part of a larger script.

For instance (psuedo-code):

codeblock = "

line 1 statements

line 2 statements

some indented statements

# a comment

line 3 statements "

arcpy.CalculateField_management("1st_dataset_name","field_to_calculate","codeblock")

arcpy.CalculateField_management("2nd_dataset_name","field_to_calculate","codeblock")

What would be the proper way of doing this?

Thanks!

Re: reusing a codeblock?

DanPatterson_Retired — Fri, 10 Dec 2021 21:16:10 GMT

just save it as a text file even inside a python script. You can enclose it inside triple-single or triple double quotes so that it won't execute, but it willl maintain its python-esque shape and form.

# my code blocks enclosed in triple-double quotes...

"""

codeblock = "
line 1 statements
line 2 statements
   some indented statements
    # a comment
line 3 statements "

"""‍‍‍‍‍‍‍‍‍‍‍‍

Re: reusing a codeblock?

DarrenWiens2 — Fri, 23 Sep 2016 20:08:48 GMT

If your codeblock is stored in a variable named "codeblock", then access it using the variable codeblock (no quotes - quotes means it's a string that literally is "codeblock")

arcpy.CalculateField_management("1st_dataset_name","field_to_calculate",codeblock)‍

Re: reusing a codeblock?

KeithD1 — Fri, 23 Sep 2016 20:28:07 GMT

I'm not sure what you mean by "save it as a text file even inside a python script". If I enclose everything in triple double quotes, then it won't execute, but it will still become a variable?

Re: reusing a codeblock?

DanPatterson_Retired — Fri, 10 Dec 2021 21:16:12 GMT

Ok... if you can save your def as a script you can import the function from within the script and reuse the code block... I suspect this isn't the easy solution that you want short of getting into importing modules, namespace and the like. but here goes.

>>> from angles_demo import _demo
>>> import inspect
>>>
>>> codeblock = inspect.getsource(_demo)
>>> print(codeblock)
def _demo():
    """A sample run of compass returning compass notations for 20 deg
       increments.  Change to suit
    """
    angles = np.arange(0, 360, 20) 
    for i in angles:
        print("{} => {}".format(i, compass(i)))
    rose = c[np.digitize(angles, a)]
    comp_rose = list(zip(angles,rose))
    print("\nCompass rose examples\n{}".format(comp_rose))
    return comp_rose
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and codeblock is a string. For you, the easiest thing would just to keep a script of your code blocks in the same folder as the script you are using... import the code block from the script and get the script. Or better still, you could just copy and paste the 'stuff' into the code you are working on... whatever is easiest is the best... but I suspect you aren't creating packages as of yet that you need to maintain.

Re: reusing a codeblock?

KeithD1 — Fri, 23 Sep 2016 21:02:25 GMT

Thanks Dan, I appreciate the response. A little over my head at this point, but maybe for my next Python project I'll be able to incorporate what you described! For now, I'll just redundantly copy-paste the codeblock where I need it to go.

Re: reusing a codeblock?

DanPatterson_Retired — Fri, 23 Sep 2016 21:31:48 GMT

good luk Keith... this topic is on my blog list. I use it all the time. It is easy once you ge the hang of it.... but copy paste is just as good...as long as you can find it