🌐 Mailman 3 November 2016 - Python-list - python.org

how to compile this code
by meInvent bbird Nov. 1, 2016

Nov. 1, 2016

would like to change Add operator to custom function op2 in solve function and then this solve([x*y - 1, x + 2], x, y) during solve, the parameters also change Add to custom function op2 import ast from __future__ import division from sympy import * x, y, z, t = symbols('x y z t') k, m, n = symbols('k m n', integer=True) f, g, h = symbols('f g h', cls=Function) import inspect def op2(a,b): return a*b+a class ChangeAddToMultiply(ast.NodeTransformer): """Wraps all integers in a call to Integer()""" def visit_BinOp(self, node): print(dir(node)) print(dir(node.left)) if isinstance(node.op, ast.Add): node.op = op2(node.left, node.right) return node code = inspect.getsourcelines(solve) tree = ast.parse(code) tree = ChangeAddToMultiply().visit(tree) ast.fix_missing_locations(tree) co = compile(tree, '<ast>', "exec") exec(code) exec(co)

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Need help with coding a function in Python
by devers.meetthebadger.jason＠gmail.com Nov. 1, 2016

Nov. 1, 2016

http://imgur.com/a/rfGhK#iVLQKSW How do I code a function that returns a list of the first n elements of the sequence defined in the link? I have no idea!!!!! So far this is my best shot at it (the problem with it is that the n that i'm subtracting or adding in the if/else part does not represent the element's position, but just the n that I am plugging into the function): def reca(n): rlist=[0] while len(rlist) < n: if (rlist[-1]-n) > 0 and (rlist[-1]-n) not in rlist: rlist.append(rlist[-1]-n) else: rlist.append(rlist[-1]+n) return(rlist)

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how to debug this distributed program?
by meInvent bbird Nov. 1, 2016

Nov. 1, 2016

https://drive.google.com/open?id=0Bxs_ao6uuBDUSEc5S3U3Nko5ZjA A. i am not sure whether parameter start from 0 or 1 n[0] or n[1] in compute function B. it run a very long time and nothing to see in amazon linux instance there is no python program in top command C. in distributed programming web site, there is no authentication method using private key in python program, how do distributed program access the nodes in amazon cloud when run python program below in window locally? import random, dispy def compute(n): # executed on nodes import random, time, socket name = socket.gethostname() cur_best = 1 for ii in range(n[0],n[0]): for jj in range(n[1],n[1]): for kk in range(n[2],n[3],100): dispy_provisional_result((name, r)) cur_best = r time.sleep(0.1) # final result return (name, cur_best) def job_callback(job): # executed at the client if job.status == dispy.DispyJob.ProvisionalResult: #if job.result[1] < 0.005: # acceptable result; terminate jobs print('%s computed: %s %s %s %s' % (job.result[0], job.result[1], job.result[2], job.result[3], job.result[4])) # 'jobs' and 'cluster' are created in '__main__' below for j in jobs: if j.status in [dispy.DispyJob.Created, dispy.DispyJob.Running, dispy.DispyJob.ProvisionalResult]: cluster.cancel(j) if __name__ == '__main__': #cluster = dispy.JobCluster(compute, callback=job_callback) cluster = dispy.JobCluster(compute, nodes=['ec2-100-162-137-237.us-west-2.compute.amazonaws.com'], callback=job_callback) jobs = [] prevk = 1 count = 0 for ii in range(1,2): for jj in range(1,2000): for kk in range(1,2000,100): if ii < jj and jj < kk: job = cluster.submit([ii,jj,prevk,kk]) prevk = kk if job is None: print('creating job %s failed!' % n) continue job.id = count count = count + 1 jobs.append(job) cluster.wait() cluster.print_status() cluster.close()

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[RELEASE] Python 3.6.0b3 is now available
by Ned Deily Nov. 1, 2016

Nov. 1, 2016

On behalf of the Python development community and the Python 3.6 release team, I'm pleased to announce the availability of Python 3.6.0b3. 3.6.0b3 is the third of four planned beta releases of Python 3.6, the next major release of Python. Among the new major new features in Python 3.6 are: * PEP 468 - Preserving the order of **kwargs in a function * PEP 487 - Simpler customization of class creation * PEP 495 - Local Time Disambiguation * PEP 498 - Literal String Formatting * PEP 506 - Adding A Secrets Module To The Standard Library * PEP 509 - Add a private version to dict * PEP 515 - Underscores in Numeric Literals * PEP 519 - Adding a file system path protocol * PEP 520 - Preserving Class Attribute Definition Order * PEP 523 - Adding a frame evaluation API to CPython * PEP 524 - Make os.urandom() blocking on Linux (during system startup) * PEP 525 - Asynchronous Generators (provisional) * PEP 526 - Syntax for Variable Annotations (provisional) * PEP 528 - Change Windows console encoding to UTF-8 (provisional) * PEP 529 - Change Windows filesystem encoding to UTF-8 (provisional) * PEP 530 - Asynchronous Comprehensions Please see "What’s New In Python 3.6" for more information: https://docs.python.org/3.6/whatsnew/3.6.html You can find Python 3.6.0b3 here: https://www.python.org/downloads/release/python-360b3/ Beta releases are intended to give the wider community the opportunity to test new features and bug fixes and to prepare their projects to support the new feature release. We strongly encourage maintainers of third-party Python projects to test with 3.6 during the beta phase and report issues found to bugs.python.org as soon as possible. While the release is feature complete entering the beta phase, it is possible that features may be modified or, in rare cases, deleted up until the start of the release candidate phase (2016-12-05). Our goal is have no changes after rc1. To achieve that, it will be extremely important to get as much exposure for 3.6 as possible during the beta phase. Please keep in mind that this is a preview release and its use is not recommended for production environments The next pre-release of Python 3.6 will be 3.6.0b4, currently scheduled for 2016-11-21. More information about the release schedule can be found here: https://www.python.org/dev/peps/pep-0494/ -- Ned Deily nad(a)python.org -- []

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Re: Call a shell command from Python (was: Calling Bash Command From Python)
by Wildman Nov. 1, 2016

Nov. 1, 2016

On Mon, 31 Oct 2016 15:44:13 +1100, Ben Finney wrote: > Wildman via Python-list <python-list(a)python.org> writes: > >> Python 2.7.9 on Linux >> >> Here is a bash command that I want to run from a python >> program: sudo grep "^user\:" /etc/shadow > > Some points to note: > > * Those commands are not special to Bash, or any particular shell. They > invoke commands, without AFAIK any specific Bash features. So this is > asking rather to invoke a shell command. Yes, I know. I perhaps should have used the word "shell" instead of bash. However, bash is a shell. > Nothing wrong with that; but on that basis, I've changed the subject > field. > > * You're asking to invoke the ‘sudo’ command, which itself is designed > to switch to a separate user identity and run another program. Yes, I know. > * The above command is (I assume) typed into a shell, but your Python > program never invokes Bash or any other shell. The program is run in a shell so invocation is not needed. >> If I enter the command directly into a terminal it works perfectly. > > Note that ‘sudo’ is specifically designed to be invoked interactively, > seeking to verify that the current user has credentials to run the > command. > > Note further that ‘sudo’ will record when the *current user session* > last invoked ‘sudo’ and seek re-verification if that is too long in the > past. > > Both of these are security measures, and are designed to avoid > non-interactive use of ‘sudo’. Rather, it's meant to be used > interactively by a real, present human with credentials to run the > command. Yes, I know all that. >> If I run it from a python program it returns an empty string. > > You can also check the exit status of a command; ‘grep’ will give > different exit status for a match versus no match. > >> Below is the code I am using. Suggestions >> appreciated. >> >> cmdlist = ["sudo", "grep", '"^$USER\:"', "/etc/shadow"] > > One immediate difference I see is that you specify different arguments > to ‘grep’. You have a different pattern for each command. > > * The ‘^user\:’ pattern matches “user\:” at the start of a line. > > * The ‘^$USER\:’ pattern I think won't match anything, since “$” matches > end-of-line and then you expect further characters *past* the end of > the line. I think that will always fail to match any line. Yes, the '^' indicates the start of the line and the ':' indicates the character where to stop. The colon has a special meaning so it has to be escaped, '\:'. The dollar sign precedes a variable. In this case it is an environment variable. The Linux shadow file contains information about the users of the system. It has the user name, encrypted password, salt, encryption type and other information. The format is such that the user name is at the start of the line ending with a colon. Here is an example: wildman:$6$hODbsJJp$/NWGXZ3fMIVB4U.v/oLtAv.CnL0l0I39.IwsDx1ZAlKW3wUSjTfwJdnQvOMpYNbqNqqFfZ52vgYWBmnjsaX9R.:16177:0:99999:7::: >> p = subprocess.Popen(cmdlist, >> stdout=subprocess.PIPE, >> stderr=subprocess.PIPE) >> shadow, err = p.communicate() > > Maybe you are expecting Bash to be involved somehow (and so “$USER” will > be substituted by Bash with some other value). That's not what happens. No, the shell is already running. And $USER will be substituted by the name of the user that invoked the shell. > Instead, the ‘subprocess.Popen.communicate’ method will invoke the > program directly, without involving a shell. See the documentation for > ‘subprocess.Popen’. I will look into that. Thanks for the reply. -- <Wildman> GNU/Linux user #557453 The cow died so I don't need your bull!

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