Trying to call a Python 3 script from a batch file when Python 2 is the default

Question

I have a batch file that calls mostly Python 2 scripts, however at the very beginning it needs to call a Python 3 script.

My Python 2 path (default, this is what is returned when I call python -V):

C:\Python27\python.exe

My Python 3 path:

C:\Users\Isaac\Anaconda3\python.exe

(The weird file structure is because I use an IDE that came with a pre-built python installation)

This is the batch file (I don't know if I actually need the timeout command or not):

for /f "tokens=2 delims=:." %%x in ('chcp') do set cp=%%x
chcp 1252>nul
start C:\Users\Isaac\Anaconda3\python.exe opennorth_downloader.py %1
timeout /t 10 /nobreak
gen_outline.py --collection objects F:\electoral_map\%1\candidates\candidates_Bloc_Québécois.json
json2csv.py F:\electoral_map\%1\candidates\candidates_Bloc_Québécois.json F:\electoral_map\%1\candidates\candidates_Bloc_Québécois.outline.json -o F:\electoral_map\%1\candidates\Bloc_Québécois.csv
del F:\electoral_map\%1\candidates\candidates_Bloc_Québécois.json
del F:\electoral_map\%1\candidates\candidates_Bloc_Québécois.outline.json
gen_outline.py --collection objects F:\electoral_map\%1\candidates\candidates_Christian_Heritage.json
json2csv.py F:\electoral_map\%1\candidates\candidates_Christian_Heritage.json F:\electoral_map\%1\candidates\candidates_Christian_Heritage.outline.json -o F:\electoral_map\%1\candidates\Christian_Heritage.csv
del F:\electoral_map\%1\candidates\candidates_Christian_Heritage.json
del F:\electoral_map\%1\candidates\candidates_Christian_Heritage.outline.json
gen_outline.py --collection objects F:\electoral_map\%1\candidates\candidates_Conservative.json
json2csv.py F:\electoral_map\%1\candidates\candidates_Conservative.json F:\electoral_map\%1\candidates\candidates_Conservative.outline.json -o F:\electoral_map\%1\candidates\Conservative.csv
del F:\electoral_map\%1\candidates\candidates_Conservative.json
del F:\electoral_map\%1\candidates\candidates_Conservative.outline.json
gen_outline.py --collection objects F:\electoral_map\%1\candidates\candidates_Forces_et_Démocratie.json
json2csv.py F:\electoral_map\%1\candidates\candidates_Forces_et_Démocratie.json F:\electoral_map\%1\candidates\candidates_Forces_et_Démocratie.outline.json -o F:\electoral_map\%1\candidates\Forces_et_Démocratie.csv
del F:\electoral_map\%1\candidates\candidates_Forces_et_Démocratie.json
del F:\electoral_map\%1\candidates\candidates_Forces_et_Démocratie.outline.json
gen_outline.py --collection objects F:\electoral_map\%1\candidates\candidates_Green_Party.json
json2csv.py F:\electoral_map\%1\candidates\candidates_Green_Party.json F:\electoral_map\%1\candidates\candidates_Green_Party.outline.json -o F:\electoral_map\%1\candidates\Green_Party.csv
del F:\electoral_map\%1\candidates\candidates_Green_Party.json
del F:\electoral_map\%1\candidates\candidates_Green_Party.outline.json
gen_outline.py --collection objects F:\electoral_map\%1\candidates\candidates_Liberal.json
json2csv.py F:\electoral_map\%1\candidates\candidates_Liberal.json F:\electoral_map\%1\candidates\candidates_Liberal.outline.json  -o F:\electoral_map\%1\candidates\Liberal.csv
del F:\electoral_map\%1\candidates\candidates_Liberal.json
del F:\electoral_map\%1\candidates\candidates_Liberal.outline.json
gen_outline.py --collection objects F:\electoral_map\%1\candidates\candidates_Libertarian.json
json2csv.py F:\electoral_map\%1\candidates\candidates_Libertarian.json F:\electoral_map\%1\candidates\candidates_Libertarian.outline.json -o F:\electoral_map\%1\candidates\Libertarian.csv
del F:\electoral_map\%1\candidates\candidates_Libertarian.json
del F:\electoral_map\%1\candidates\candidates_Libertarian.outline.json
gen_outline.py --collection objects F:\electoral_map\%1\candidates\candidates_NDP.json
json2csv.py F:\electoral_map\%1\candidates\candidates_NDP.json F:\electoral_map\%1\candidates\candidates_NDP.outline.json -o F:\electoral_map\%1\candidates\NDP.csv
del F:\electoral_map\%1\candidates\candidates_NDP.json
del F:\electoral_map\%1\candidates\candidates_NDP.outline.json
chcp %cp%>nul
pause

I know that everything works except for this line:

start C:\Users\Isaac\Anaconda3\python.exe opennorth_downloader.py %1

(The batch file worked when it was run without it with what it does set up in advance)

This is the script that it references:

from sys import argv
import urllib

party_name_list = ["Conservative", "Liberal", "NDP", "Green Party", "Bloc Québécois", "Forces et Démocratie", "Libertarian", "Christian Heritage"]

for party_name in party_name_list:
    with urllib.request.urlopen(r"https://represent.opennorth.ca/candidates/house-of-commons/?limit=1000&party_name={}".format(urllib.parse.quote_plus(party_name))) as url:
        with open(r"F:\electoral_map\{0}\candidates\candidates_{1}.json".format(argv[1], party_name.replace(' ', '_')), "wb+") as f:
            f.write(url.read())
    print("finished {0}".format(party_name))
print("all done")

The batch file is called with a single argument: "20150915" which represents a date and points everything to a single folder that everything is contained within.

Can anybody see a reason why that problem line would fail? It looks like what it is supposed to be according to this

I guess I don't know for sure, the cmd window that I call from batch file from launches a new window that instantly terminates, but all the rest of the commands fail due to lack of pre-requisite files that are supposed to be generated by that "problem line". If I set up the folder with the outputs of opennorth_downloader after I run it in my IDE, and then exclude the batch file without that problem line, the batch file executes without incident. — wfgeo
– wfgeo, Commented Sep 16, 2015 at 2:14
No, it doesn't. I will try that when I get home, thanks, wOxxOm — wfgeo
– wfgeo, Commented Sep 16, 2015 at 16:04
try to replace %1 by %~1 in start C:\Users\Isaac\Anaconda3\python.exe opennorth_downloader.py %1 or try set "myvar=%~1" & start C:\Users\Isaac\Anaconda3\python.exe opennorth_downloader.py %myvar% — Paul
– Paul, Commented Sep 16, 2015 at 17:38

wfgeo · Accepted Answer · 2015-09-17 00:57:18Z

0

I was finally able to solve it after a LOT of digging and mucking around. For some unknown reason, the .bat does not recognize the "request" module of urllib unless it is explicitly imported, like so:

from sys import argv
from urllib import request
from urllib import parse

party_name_list = ["Conservative", "Liberal", "NDP", "Green Party", "Bloc Québécois", "Forces et Démocratie", "Libertarian", "Christian Heritage"]

for party_name in party_name_list:
    with request.urlopen(r"https://represent.opennorth.ca/candidates/house-of-commons/?limit=1000&party_name={}".format(parse.quote_plus(party_name))) as url:
        with open(r"F:\electoral_map\{0}\candidates\candidates_{1}.json".format(argv[1], party_name.replace(' ', '_')), "wb+") as f:
            f.write(url.read())
    print("finished {0}".format(party_name))
print("all done")

Then it works with no issue using the same batch file as above. I have no idea why but at this point I'm just happy it's working :)

answered Sep 17, 2015 at 0:57

wfgeo

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6 Comments

jfs Over a year ago

in general, import a does not also import a.b. If you need a.b; you must import a.b.

jfs Over a year ago

unrelated: you could use shutil.copyfileobj(url, f), to avoid loading the whole content into memory first or just use urllib.request.urlretrieve('https://...', r'F:\...json'). You could also make the http requests concurrently

wfgeo Over a year ago

J.F. Sebastian: I'm aware of that, but my original script had the full name in a.b.c form, for some reason the batch file just didn't like having to call a.b.c even when all of a was imported. The script actually worked in my IDE, just failed when called in cmd

jfs Over a year ago

Try from the command-line: py -3 -c "import urllib; urllib.request" -- it should fail. If it doesn't fail in your IDE; it is broken (it doesn't isolate the execution of your script sufficiently). py -3 -c "import urllib.request; urllib.request" should not fail.

jfs Over a year ago

because it means that IDE does things behind your back. In your case, it makes your incorrect program run without an error (who knows what other side-effects it introduces -- it is not safe to import arbitrary modules left and right -- any code can be run at import time -- prey that you don't have a module with shutil.rmtree('/') lying around). You must import urllib.request if you want to use urllib.request module.

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