I downloaded pip and ran `python setup.py install` and everything worked just fine. The very next step in the tutorial is to run `pip install &lt;lib you want&gt;` but before it even tries to find anything online I get an error &quot;bash: pip: command not found&quot;.

This is on Mac OS X, which I&#39;m new to, so I&#39;m assuming there&#39;s some kind of path setting that was not set correctly when I ran `setup.py`. How can I investigate further? What do I need to check to get a better idea of the exact cause of the problem?

**EDIT:** I also tried installing Python 2.7 for Mac in the hopes that the friendly install process would do any housekeeping like editing PATH and whatever else needs to happen for everything to work according to the tutorials, but this didn&#39;t work. After installing, running &#39;python&#39; still ran Python 2.6 and PATH was not updated.

bash: pip: command not found

Is there a way to get **all** attributes/methods/fields/etc. of an object in Python?

`vars()` is *close* to what I want, but it doesn&#39;t work unless an object has a `__dict__`, which isn&#39;t always true (e.g. it&#39;s not true for a `list`, a `dict`, etc.).

Get all object attributes in Python?

I am writing scripts in Python2.6 with use of [pyVmomi](https://github.com/vmware/pyvmomi) and while using one of the connection methods:

    service_instance = connect.SmartConnect(host=args.ip,
                                            user=args.user,
                                            pwd=args.password)

I get the following warning:

    /usr/lib/python2.6/site-packages/requests/packages/urllib3/connectionpool.py:734: InsecureRequestWarning: Unverified HTTPS request is being made. Adding certificate verification is strongly advised. See: https://urllib3.readthedocs.org/en/latest/security.html
      InsecureRequestWarning)


What&#39;s interesting is that I do not have urllib3 installed with pip (but it&#39;s there in */usr/lib/python2.6/site-packages/requests/packages/urllib3/*).

I have tried as suggested [here](https://urllib3.readthedocs.org/en/latest/security.html)

    import urllib3
    ...
    urllib3.disable_warnings()

but that didn&#39;t change anything.



Suppress InsecureRequestWarning: Unverified HTTPS request is being made in Python2.6

In **Python 2.6**, I want to do:

    f = lambda x: if x==2 print x else raise Exception()
    f(2) #should print &quot;2&quot;
    f(3) #should throw an exception

This clearly isn&#39;t the syntax. Is it possible to perform an `if` in `lambda` and if so how to do it?

Is there a way to perform &quot;if&quot; in python&#39;s lambda?

What is the difference between &#39;,&#39; and &#39;as&#39; in except statements, eg:

    try:
        pass
    except Exception, exception:
        pass

and:

    try:
        pass
    except Exception as exception:
        pass

Is the second syntax legal in 2.6?  It works in CPython 2.6 on Windows but the 2.5 interpreter in cygwin complains that it is invalid.

If they are both valid in 2.6 which should I use?


Python try...except comma vs &#39;as&#39; in except

I&#39;ve run into a bit of a wall importing modules in a Python script. I&#39;ll do my best to describe the error, why I run into it, and why I&#39;m tying this particular approach to solve my problem (which I will describe in a second):

Let&#39;s suppose I have a module in which I&#39;ve defined some utility functions/classes, which refer to entities defined in the namespace into which this auxiliary module will be imported (let &quot;a&quot; be such an entity):

module1:

    def f():
        print a


And then I have the main program, where &quot;a&quot; is defined, into which I want to import those utilities:

    import module1
    a=3
    module1.f()

Executing the program will trigger the following error:

    Traceback (most recent call last):
      File &quot;Z:\Python\main.py&quot;, line 10, in &lt;module&gt;
        module1.f()
      File &quot;Z:\Python\module1.py&quot;, line 3, in f
        print a
    NameError: global name &#39;a&#39; is not defined

[Similar questions have been asked][1] in the past (two days ago, d&#39;uh) and several solutions have been suggested, however I don&#39;t really think these fit my requirements. **Here&#39;s my particular context:**

I&#39;m trying to make a Python program which connects to a MySQL database server and displays/modifies data with a GUI. For cleanliness sake, I&#39;ve defined the bunch of auxiliary/utility MySQL-related functions in a separate file. However they all have a common variable, which I had originally defined *inside* the utilities module, and which is the *cursor* object from MySQLdb module.
I later realised that the *cursor* object (which is used to communicate with the db server) should be defined in the main module, **so that both the main module and anything that is imported into it can access that object.**

End result would be something like this:

utilities_module.py:

    def utility_1(args):
        code which references a variable named &quot;cur&quot;
    def utility_n(args):
        etcetera

And my main module:

program.py:

    import MySQLdb, Tkinter
    db=MySQLdb.connect(#blahblah) ; cur=db.cursor()  #cur is defined!
    from utilities_module import *

And then, as soon as I try to call any of the utilities functions, it triggers the aforementioned &quot;global name not defined&quot; error.

A particular suggestion was to have a &quot;from program import cur&quot; statement in the utilities file, such as this:

utilities_module.py:

    from program import cur
    #rest of function definitions

program.py:

    import Tkinter, MySQLdb
    db=MySQLdb.connect(#blahblah) ; cur=db.cursor()  #cur is defined!
    from utilities_module import *

But that&#39;s cyclic import or something like that and, bottom line, it crashes too. So my question is:

**How in hell can I make the &quot;cur&quot; object, defined in the main module, visible to those auxiliary functions which are imported into it?**

Thanks for your time and my deepest apologies if the solution has been posted elsewhere. I just can&#39;t find the answer myself and I&#39;ve got no more tricks in my book.



  [1]: https://stackoverflow.com/questions/15890014/python-namespaces-with-module-imports

Visibility of global variables in imported modules

I am trying to convert a set to a list in Python 2.6. I&#39;m using this syntax:

    first_list = [1,2,3,4]
    my_set=set(first_list)
    my_list = list(my_set)

However, I get the following stack trace:

    Traceback (most recent call last):
      File &quot;&lt;console&gt;&quot;, line 1, in &lt;module&gt;
    TypeError: &#39;set&#39; object is not callable

How can I fix this?

How to convert a set to a list in python?

I am confused as to why the following code snippet would not exit when called in the thread, but would exit when called in the main thread.

	import sys, time
	from threading import Thread

	def testexit():
		time.sleep(5)
		sys.exit()
		print &quot;post thread exit&quot;

	t = Thread(target = testexit)
	t.start()
	t.join()
	print &quot;pre main exit, post thread exit&quot;
	sys.exit()
	print &quot;post main exit&quot;

The docs for `sys.exit()` state that the call should exit from Python. I can see from the output of this program that &quot;post thread exit&quot; is never printed, but the main thread just keeps on going even after the thread calls exit. 

Is a separate instance of the interpreter being created for each thread, and the call to `exit()` is just exiting that separate instance? If so, how does the threading implementation manage access to shared resources? What if I did want to exit the program from the thread (not that I actually want to, but just so I understand)?

Why does sys.exit() not exit when called inside a thread in Python?

How can I get the class that defined a method in Python?

I&#39;d want the following example to print &quot;`__main__.FooClass`&quot;:

    class FooClass:
        def foo_method(self):
            print &quot;foo&quot;
            
    class BarClass(FooClass):
        pass
        
    bar = BarClass()
    print get_class_that_defined_method(bar.foo_method)



Get class that defined method

I want to run a command in `pythong`, using the subprocess module, and store the output in a variable. However, I do not want the command&#39;s output to be printed to the terminal.
For this code:

    def storels():
       a = subprocess.Popen(&quot;ls&quot;,shell=True)
    storels()

I get the directory listing in the terminal, instead of having it stored in `a`. I&#39;ve also tried:

     def storels():
           subprocess.Popen(&quot;ls &gt; tmp&quot;,shell=True)
           a = open(&quot;./tmp&quot;)
           [Rest of Code]
     storels()

This also prints the output of ls to my terminal. I&#39;ve even tried this command with the somewhat dated os.system method, since running `ls &gt; tmp` in the terminal doesn&#39;t print `ls` to the terminal at all, but stores it in `tmp`. However, the same thing happens.


**Edit:**

I get the following error after following marcog&#39;s advice, but only when running a more complex command. `cdrecord --help`. Python spits this out:



    Traceback (most recent call last):
      File &quot;./install.py&quot;, line 52, in &lt;module&gt;
        burntrack2(&quot;hi&quot;)
      File &quot;./install.py&quot;, line 46, in burntrack2
        a = subprocess.Popen(&quot;cdrecord --help&quot;,stdout = subprocess.PIPE)
      File &quot;/usr/lib/python2.6/subprocess.py&quot;, line 633, in __init__
        errread, errwrite)
      File &quot;/usr/lib/python2.6/subprocess.py&quot;, line 1139, in _execute_child
        raise child_exception
    OSError: [Errno 2] No such file or directory




Pipe subprocess standard output to a variable

I installed `Python 2.6` and `Python 3.1` on Windows 7 and set environment variable: `path = d:\python2.6`. 

When I run `python` in `cmd`, it displays the python version 2.6, which is what I want! &lt;br /&gt;
But, when I wrote a script in a bat file and ran it, the displayed python version was 3.1.


    import sys
    print (sys.version)


What&#39;s going on here? 


How Should I Set Default Python Version In Windows?

We&#39;ve already gotten our code base running under Python 2.6.  In order to prepare for Python 3.0, we&#39;ve started adding:

&lt;pre&gt;
from __future__ import unicode_literals
&lt;/pre&gt;

into our `.py` files (as we modify them).  I&#39;m wondering if anyone else has been doing this and has run into any non-obvious gotchas (perhaps after spending a lot of time debugging).

Any gotchas using unicode_literals in Python 2.6?

Assume that I have a dict.
  

    data = {1:&#39;b&#39;, 2:&#39;a&#39;}

And I want to sort data by &#39;b&#39; and &#39;a&#39; so I get the result

    &#39;a&#39;,&#39;b&#39;

How do I do that?  
Any ideas?





sort dict by value python

I&#39;ve been trying to find a more pythonic way of generating random string in python that can scale as well. Typically, I see something similar to

    &#39;&#39;.join(random.choice(string.letters) for i in xrange(len))

It sucks if you want to generate long string.

I&#39;ve been thinking about random.getrandombits for a while, and figuring out how to convert that to an array of bits, then hex encode that. Using python 2.6 I came across the bitarray object, which isn&#39;t documented.  Somehow I got it to work, and it seems really fast.

It generates a 50mil random string on my notebook in just about 3 seconds.

    def rand1(leng):
        nbits = leng * 6 + 1
        bits = random.getrandbits(nbits)
        uc = u&quot;%0x&quot; % bits
        newlen = int(len(uc) / 2) * 2 # we have to make the string an even length
        ba = bytearray.fromhex(uc[:newlen])
        return base64.urlsafe_b64encode(str(ba))[:leng]

---
**edit**

heikogerlach pointed out that it was an odd number of characters causing the issue. New code added to make sure it always sent fromhex an even number of hex digits.

Still curious if there&#39;s a better way of doing this that&#39;s just as fast.


Random strings in Python 2.6 (Is this OK?)

# Background #

I am using SQLite to access a database and retrieve the desired information. I&#39;m using ElementTree in Python version 2.6 to create an XML file with that information.

# Code #

    import sqlite3
    import xml.etree.ElementTree as ET

    # NOTE: Omitted code where I acccess the database,
    # pull data, and add elements to the tree
    
    tree = ET.ElementTree(root)
    
    # Pretty printing to Python shell for testing purposes
    from xml.dom import minidom
    print minidom.parseString(ET.tostring(root)).toprettyxml(indent = &quot;   &quot;)
    
    #######  Here lies my problem  #######
    tree.write(&quot;New_Database.xml&quot;)


# Attempts #

I&#39;ve tried using &lt;code&gt;tree.write(&quot;New_Database.xml&quot;, &quot;utf-8&quot;)&lt;/code&gt; in place of the last line of code above, but it did not edit the XML&#39;s layout at all - it&#39;s still a jumbled mess.

I also decided to fiddle around and tried doing:&lt;br&gt;
&lt;code&gt;tree = minidom.parseString(ET.tostring(root)).toprettyxml(indent = &quot;   &quot;)&lt;br&gt;&lt;/code&gt; instead of printing this to the Python shell, which gives the error &lt;b&gt;AttributeError: &#39;unicode&#39; object has no attribute &#39;write&#39;&lt;/b&gt;.

# Questions #

When I write my tree to an XML file on the last line, is there a way to pretty print to the XML file as it does to the Python shell?

Can I use &lt;code&gt;toprettyxml()&lt;/code&gt; here or is there a different way to do this?

How do I get Python&#39;s ElementTree to pretty print to an XML file?

Does anyone have a simple example using ast.NodeVisitor to walk the abstract syntax tree in Python 2.6? The difference between visit and generic_visit is unclear to me, and I cannot find any example using google codesearch or plain google.

Simple example of how to use ast.NodeVisitor?

In python 2.6, the following code:
    
    import urlparse
    qsdata = &quot;test=test&amp;test2=test2&amp;test2=test3&quot;
    qs = urlparse.parse_qs(qsdata)
    print qs

Gives the following output:

    {&#39;test&#39;: [&#39;test&#39;], &#39;test2&#39;: [&#39;test2&#39;, &#39;test3&#39;]}

Which means that even though there is only one value for test, it is still being parsed into a list. Is there a way to ensure that if there&#39;s only one value, it is not parsed into a list, so that the result would look like this?

    {&#39;test&#39;: &#39;test&#39;, &#39;test2&#39;: [&#39;test2&#39;, &#39;test3&#39;]}


How to stop Python parse_qs from parsing single values into lists?

I have Python 2.6 in my Linux rhel-5. I have installed pip and required CFFI packages. When I try to run a sample CFFI program:

    ffi = FFI()

it says:
```
File &quot;/usr/lib/python2.6/site-packages/cffi/api.py&quot;, line 56, in __init__
    import _cffi_backend as backend
ImportError: No module named _cffi_backend
```
What could be the possible error? Did I miss something during installation? I have installed pip, wheel, pycparser, pytest and cffi.


 

No module named _cffi_backend

Many try/except/finally-clauses not only &quot;uglify&quot; my code, but i find myself often using identical exception-handling for similar tasks. So i was considering reducing redundancy by &quot;outsourcing&quot; them to a ... decorator.

Because i was sure not to be the 1st one to come to this conclusion, I googled and found this - imho - ingenious [recipe][1] which added the possibility to handle more than one exception.

But i was surprised why this doesn&#39;t seem to be a wide known and used practice per se, so i was wondering if there is maybe an aspect i wasn&#39;t considering? 

1. Is it bogus to use the decorator pattern for exception-handling or did i just miss it the whole time? Please enlighten me! What are the pitfalls? 

2. Is there maybe even a package/module out there which supports the creation of such exception-handling in a reasonable way?

  [1]: http://code.activestate.com/recipes/408937-basic-exception-handling-idiom-using-decorators/

&quot;outsourcing&quot; exception-handling to a decorator

I have a python 2.6 script (yes I know I should upgrade to at least 2.7) that looks like this:

    ret_code = 0
    
    def some_func()
      global ret_code
      ...

    if __name__ == &#39;__main__&#39;:
      global ret_code
      ...

Now I get a warning if I run the code:
*SyntaxWarning: name &#39;ret_code&#39; is assigned to before global declaration global ret_code*

Why do I get this warning?

I can solve the problem by doing so:


    def some_func()
          global ret_code
          ...

    if __name__ == &#39;__main__&#39;:
      global ret_code
      ret_code = 0 #assign 0 here instead of above
      ...

Still that doesn&#39;t answer my question. What is wrong with the original code?


All Python 2.6 Solutions on Gang of Coders

Total of 20 Python 2.6 Solutions