Re: int.to_bytes() for a single byte
On Tuesday, November 6, 2018 at 7:19:09 PM UTC-8, Terry Reedy wrote: > On 11/6/2018 9:30 PM, j...y@it.u wrote: > > > b = i.to_bytes(1, "big") > > > >Is there another function which provides a more logical interface to this > >straightforward task? > > Yes > >>> 33 .to_bytes(1, 'big') > b'!' > >>> bytes((33,)) > b'!' Thanks Terry, that's what I was looking for. I had tried using the bytes() constructor directly, and was getting a byte array of zeros, of the length specified by the integer. That's in the documentation, and it might be useful, but I haven't seen an obvious use case, and it isn't what I wanted. Wrapping the integer in a tuple solves the problem of it being interpreted as a length. -- https://mail.python.org/mailman/listinfo/python-list
Re: int.to_bytes() for a single byte
On 11/6/2018 9:30 PM, jlada...@itu.edu wrote: b = i.to_bytes(1, "big") Is there another function which provides a more logical interface to this straightforward task? Yes >>> 33 .to_bytes(1, 'big') b'!' >>> bytes((33,)) b'!' See >>> bytes( # in IDLE or >>> help(bytes) -- Terry Jan Reedy -- https://mail.python.org/mailman/listinfo/python-list
Re: int.to_bytes() for a single byte
On 11/6/2018 9:30 PM, jlada...@itu.edu wrote: I'm using Python 3.6. I have a need to convert several small integers into single bytes. As far as I can tell from reading through the Python docs, the correct way to accomplish this task is: b = i.to_bytes(1, "big") This seems to work, but I find it cumbersome. I have to supply the byteorder argument to prevent a TypeError. However, byte order doesn't matter if I'm only generating a single byte. Whether I choose "big" or "little" I should get the same result. Is there another function which provides a more logical interface to this straightforward task? Take a look at the struct module. Bob Gailer -- https://mail.python.org/mailman/listinfo/python-list
int.to_bytes() for a single byte
I'm using Python 3.6. I have a need to convert several small integers into single bytes. As far as I can tell from reading through the Python docs, the correct way to accomplish this task is: b = i.to_bytes(1, "big") This seems to work, but I find it cumbersome. I have to supply the byteorder argument to prevent a TypeError. However, byte order doesn't matter if I'm only generating a single byte. Whether I choose "big" or "little" I should get the same result. Is there another function which provides a more logical interface to this straightforward task? Thanks for any suggestions. -- https://mail.python.org/mailman/listinfo/python-list
Re: Asyncio tasks getting cancelled
On Tue, Nov 6, 2018 at 3:39 PM Ian Kelly wrote: > > n Mon, Nov 5, 2018 at 8:43 PM wrote: > > What I meant was, the error message is specific to futures in the > > 'PENDING' state. Which should be set to 'RUNNING' before any actions > > occur. So it appears the tasks weren't started at all. > > Ah. I don't think asyncio uses a RUNNING state. There's nothing about > it in the docs; tasks are either done or they're not: > https://docs.python.org/3/library/asyncio-task.html#task-object > > And inspecting the current task also shows PENDING: > > py> from asyncio import * > py> async def main(): > ... print(current_task()._state) > ... > py> run(main()) > PENDING Looks like the only states are PENDING, CANCELLED, and FINISHED: https://github.com/python/cpython/blob/3.7/Lib/asyncio/base_futures.py#L17 -- https://mail.python.org/mailman/listinfo/python-list
Re: Asyncio tasks getting cancelled
n Mon, Nov 5, 2018 at 8:43 PM wrote: > > On Mon, Nov 05, 2018 at 07:15:04PM -0700, Ian Kelly wrote: > > > For context: > > > https://github.com/ldo/dbussy/issues/13 > > > https://gist.github.com/tu500/3232fe03bd1d85b1529c558f920b8e43 > > > > > > It really feels like asyncio is loosing strong references to scheduled > > > tasks, as excplicitly keeping them around helps. Also, the error > > > messages I'm getting are the ones from here: > > > https://github.com/python/cpython/blob/16c8a53490a22bd4fcde2efaf4694dd06ded882b/Lib/asyncio/tasks.py#L145 > > > Which indicates that the tasks actually weren't even started at all? > > > > No, it indicates that it was cleaned up (likely because the program > > exited) before the task completed. Which likely implies that the loop > > exited without waiting for it. From the stack trace, you're using > > loop.run_until_complete(main()). Like asyncio.run, that only runs > > until the specific thing you pass it completes, which might wait on > > other things or might not. Anything else that's still pending is going > > to be left up in the air unless you subsequently restart the same > > event loop. > > What I meant was, the error message is specific to futures in the > 'PENDING' state. Which should be set to 'RUNNING' before any actions > occur. So it appears the tasks weren't started at all. Ah. I don't think asyncio uses a RUNNING state. There's nothing about it in the docs; tasks are either done or they're not: https://docs.python.org/3/library/asyncio-task.html#task-object And inspecting the current task also shows PENDING: py> from asyncio import * py> async def main(): ... print(current_task()._state) ... py> run(main()) PENDING > Also the cleanup happens instantly, ie before the loop exits (as the > main loop has an asyncio.sleep timeout. Printing a message also clearly > shows this happens way before main returns. Okay, that wasn't clear from the log you posted. It's not obvious to me why that would be happening. although it does sound like the tasks are getting created and then immediately garbage-collected for some reason. It could be a bug in asyncio, or it could be a bug in the way the tasks are created, e.g. on a separate event loop that gets dropped on the floor. -- https://mail.python.org/mailman/listinfo/python-list
Re: Overwhelmed by the Simplicity of Python. Any Recommendation?
> I like to step through my code line by line, > it's impossible to do it with > object-oriented programming language. I suggest pudb, it's a curses based debugger, which is nicer than pdb, but doesn't require tedious IDE setup. > Also, there's no good REPL IDE. Not quite sure what you meant by REPL IDE, but did you try IPython -- https://mail.python.org/mailman/listinfo/python-list
Re: SyntaxError: can't assign to literal while using ""blkid -o export %s | grep 'TYPE' | cut -d"=" -f3" % (fs)" using subprocess module in Python
On 06/11/2018 18:10, srinivasan wrote: root:~/qa/test_library# python3 sd.py File "sd.py", line 99 *cmd = "blkid -o export %s | grep 'TYPE' | cut -d"=" -f3" % (fs)* * ^* *SyntaxError: can't assign to literal* Look at the 'cut' element of the pipeline. You have used double quotes in a double quoted string without escaping them. As a result, the interpreter thinks you are trying to assign the string literal " -f3" to the string literal "blkid -o export %s | grep 'Type' | cut -d" -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
SyntaxError: can't assign to literal while using ""blkid -o export %s | grep 'TYPE' | cut -d"=" -f3" % (fs)" using subprocess module in Python
Dear Python Experts Team,
As am newbie to python development, I am trying to use the below function
to get verify the filesystem type of the SD card parition using bash
command in python using subprocess module, I ma seeing the below Error
"SyntaxError: can't assign to literal"
*CODE:*
**
import helper
from os import path
import subprocess
import os
import otg_ni
class emmc(object):
"""
emmc getters and setters
info:
https://www.kernel.org/doc/Documentation/cpu-freq/user-guide.txt
"""
def __init__(self):
self._helper = helper.helper()
self._otg_ni = otg_ni.otg_ni()
*def get_fstype_of_mounted_partition(self, fs):*
"""
Get the filesystem type of the mounted partition.
:partition_name : Partition path as string (e.g. /dev/mmcblk0p1)
:return: filesystem type as string or None if not found
"""
*cmd = "blkid -o export %s | grep 'TYPE' | cut -d"=" -f3" % (fs)*
*return self._helper.execute_cmd_output_string(cmd)*
*def execute_cmd_output_string(self, cmd, enable_shell=False):*
"""
Execute a command and return its output as a string.
:param cmd: abs path of the command with arguments
:param enable_shell : force the cmd to be run as shell script
:return: a string.
"""
try:
result = subprocess.check_output(split(cmd),
stderr=subprocess.STDOUT,
shell=enable_shell)
except subprocess.CalledProcessError as e:
s = """While executing '{}' something went wrong.
Return code == '{}'
Return output:\n'{}'
""".format(cmd, e.returncode, e.output, shell=enable_shell)
raise AssertionError(s)
return result.strip().decode("utf-8")
*if __name__ == "__main__":*
m = emmc()
*m.get_fstype_of_mounted_partition("/dev/mmcblk0p1")*
*Error:*
*==*
root:~/qa/test_library# python3 sd.py
File "sd.py", line 99
*cmd = "blkid -o export %s | grep 'TYPE' | cut -d"=" -f3" % (fs)*
* ^*
*SyntaxError: can't assign to literal*
root:~/qa/test_library#
Kindly do the needful as early as possible, as am stuck with this issue
from past 2 days no clues yet, please redirect me to the correct forum if
this is not the right place for pasting python related queries
Many Thanks in advance,
Srini
--
https://mail.python.org/mailman/listinfo/python-list
Re: Unable to remove python from my computer.
On 06/11/2018 09:25, Thomas Jollans wrote: On 2018-11-06 10:05, Varshit Jain wrote: Hi Python Support Team, I just want to remove python 3.6.6 from my computer. I am unable to do it. Please find attached video that describe my problem. Use your words, friend! (this list is text-only) More exactly, I'm afraid the mailing list has stripped off the video you attached, so we can't watch it. I'm afraid I wouldn't in any case; I learned long ago not to open attachments from people I don't already know. Could you please describe to us your problem? Are you using Windows, Linux, Mac or something else? Copy any error messages the uninstaller might have given you, preferably cutting and pasting rather than just retyping them (it's easy to mistype something critical!). Please don't send us screen shots, those will just get stripped off by the mailing list as well. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Unable to remove python from my computer.
On 2018-11-06 10:05, Varshit Jain wrote: > Hi Python Support Team, > > > I just want to remove python 3.6.6 from my computer. I am unable to do > it. Please find attached video that describe my problem. Use your words, friend! (this list is text-only) -- https://mail.python.org/mailman/listinfo/python-list
Unable to remove python from my computer.
Hi Python Support Team, I just want to remove python 3.6.6 from my computer. I am unable to do it. Please find attached video that describe my problem. Suggest me solution / Steps to remove python from my PC. Regards, Varshit Jain -- https://mail.python.org/mailman/listinfo/python-list
