You need to install the Python development files.  I believe this will do it:

    sudo apt-get install python-dev


On Ubuntu, I needed some other packages for it to succeed:

    apt-get install autoconf g++ python2.7-dev
    pip install pycrypto


On Ubuntu and if you use Python 3.x you will need:

    sudo apt-get install gcc python3-dev

you probably already have gcc but just in case if you are trying this command from Dockerfile with base image python:3.6.4-slim-jessie then you will also need gcc.

**August 2021**

For python 3.8 users run

    sudo apt-get install python3.8-dev

and try to install pycrypto again 

    pip install pycrypto

In python I can do this:

&lt;!-- language: lang-py --&gt;

    def f((a, b)):
        return a + b

    d = (1, 2)
    f(d)

Here the passed in tuple is being decomposed while its being passed to `f`.

Right now in scala I am doing this:

&lt;!-- language: lang-scala --&gt;

    def f(ab: (Int, Int)): Int = {
        val (a, b) = ab
        a + b
    }

    val d = (1, 2)
    f(d)

Is there something I can do here so that the decomposition happens while the arguments are passed in? Just curious.


Decomposing tuples in function arguments

I&#39;m trying to put breakpoints into the GoogleAppEngine sources (SDK 1.7.0) but IDEA Ultimate (11.0.2) just keeps telling me `Warning: No executable code found at line 482 in class com.google.appengine.api.memcache.AsyncMemcacheServiceImpl`.

I get this error message both when I run the code from unit tests and I start up the development server.

It&#39;s quite annonying. Anyway my sources are in an external (relative to both the IDEA home and the project home) directory, and my jar files are under the Appengine SDK lib dir.

My jar files are added as project library to the module, and my sources are attached to this library. I was playing around with module dependencies as well, but without any luck. Finally I decided to put this library into Compile scope, but that was a bad idea since the SDK provides these jars at runtime, so I decided to fall back to Provided scope.

I also played with the export checkbox on the module dependencies tab, but I think this is irrelevant, according to the [web help][1], export is only important when you have dependent modules and you want to make your library available in these modules as well.

Anyway, this question arised [4 years ago][2] also. So I&#39;m wondering now whether is it really so hard to solve this issue?

I&#39;m very disappointed now. I didn&#39;t have any problems with IDEA so far... I saw that this problem [arised to other people][3] as well, so this is not unique I guess.

Any help is appreciated.


----------
I edited my question due to my `javap` experiments below: It seems that the classes and the sources are **NOT** out of sync. I checked out the 1.7.0 related revision from SVN, and I&#39;m using the 1.7.0 SDK, so these should not be out of sync at all.

  [1]: http://www.jetbrains.com/idea/webhelp/dependencies-tab.html
  [2]: http://devnet.jetbrains.net/thread/276796
  [3]: https://stackoverflow.com/questions/11199282/set-a-breakpoint-inside-a-library-jar-in-intellij

Cannot set Java breakpoint in Intellij IDEA

Having looked at other similar threads, I still can&#39;t get pycrypto running.

I&#39;m trying to get it working on my Ubuntu laptop - but I couldn&#39;t manage it on my Windows PC either.

I downloaded pycrypto-2.6, extracted it, and ran

        python setup.py build

but then this happened

    warning: GMP or MPIR library not found; Not building Crypto.PublicKey._fastmath.
    building &#39;Crypto.Hash._MD2&#39; extension
    gcc -pthread -fno-strict-aliasing -fwrapv -Wall -Wstrict-prototypes -fPIC -std=c99 -O3 - fomit-frame-pointer -Isrc/ -I/usr/include/python2.7 -c src/MD2.c -o build/temp.linux-i686-?2.7/src/MD2.o
    src/MD2.c:31:20: fatal error: Python.h: No such file or directory
    compilation terminated.
    error: command &#39;gcc&#39; failed with exit status 1


Would appreciate any help.

Installing PyCrypto on Ubuntu - fatal error on build

Having looked at other similar threads, I still can't get pycrypto running.
I'm trying to get it working on my Ubuntu laptop - but I couldn't manage it on my Windows PC either.
I downloaded pycrypto-2.6, extracted it, and ran
<pre><code class="hljs language-arduino"> python setup.py build
</code></pre>
but then this happened
<pre><code class="hljs language-bash">warning: GMP or MPIR library not found; Not building Crypto.PublicKey._fastmath.
building 'Crypto.Hash._MD2' extension
gcc -pthread -fno-strict-aliasing -fwrapv -Wall -Wstrict-prototypes -fPIC -std=c99 -O3 - fomit-frame-pointer -Isrc/ -I/usr/include/python2.7 -c src/MD2.c -o build/temp.linux-i686-?2.7/src/MD2.o
src/MD2.c:31:20: fatal error: Python.h: No such file or directory
compilation terminated.
error: command 'gcc' failed with exit status 1
</code></pre>
Would appreciate any help.

I am curious why in Python a trailing comma in a list is valid syntax, and it seems that Python simply ignores it:

    &gt;&gt;&gt; [&#39;a&#39;,&#39;b&#39;,]
    [&#39;a&#39;, &#39;b&#39;]

It makes sense when its a tuple since `(&#39;a&#39;)` and `(&#39;a&#39;,)` are two different things, but in lists?



Why are trailing commas allowed in a list?

I was a bit curious if I could do more work in a function after returning a result.  Basically I&#39;m making a site using the pyramid framework(which is simply coding in python) after I process the inputs I return variables to render the page but sometimes I want to do more work after I render the page.

For example, you come to my site and update your profile and all you care about is that its successful so I output a message saying &#39;success!&#39; but after that done I want to take your update and update my activity logs of what your doing, update your friends activity streams, etc..  Right now I&#39;m doing all that before I return the result status that you care about but I&#39;m curious if I can do it after so users get their responses faster.

I have done multi-processing before and worst case I might just fork a thread to do this work but if there was a way to do work after a return statement then that would be simpler.

example:

    def profile_update(inputs):
      #take updates and update the database 
      return &quot;it worked&quot;
      #do maintenance processing now.



Is there a way to do more work after a return statement?

&gt; **Possible Duplicate:**  
&gt; [How to get current CPU and RAM usage in Python?](https://stackoverflow.com/questions/276052/how-to-get-current-cpu-and-ram-usage-in-python)  

&lt;!-- End of automatically inserted text --&gt;

How can I get the available and currently used memory from Python? It need to be cross-platform and at least work on at least Windows, Mac OS X and Linux.

I&#39;d like to report the user in my application that he doesn&#39;t have enough memory free to proceed and do the next operation.


Available and used System Memory in Python?

Is there any python package that allows the efficient computation of the PDF (probability density function) of a [multivariate normal distribution][1]?

It doesn&#39;t seem to be included in Numpy/Scipy, and surprisingly a Google search didn&#39;t turn up any useful thing.


  [1]: https://en.wikipedia.org/wiki/Multivariate_normal_distribution

Multivariate normal density in Python?

I am having trouble installing psycopg2. I get the following error when I try to `pip install psycopg2`:

    Error: pg_config executable not found.
    
    Please add the directory containing pg_config to the PATH
    
    or specify the full executable path with the option:
    
    
    
        python setup.py build_ext --pg-config /path/to/pg_config build ...
    
    
    
    or with the pg_config option in &#39;setup.cfg&#39;.
    
    ----------------------------------------
    Command python setup.py egg_info failed with error code 1 in /tmp/pip-build/psycopg2


But the problem is `pg_config` is actually in my `PATH`; it runs without any problem:

    $ which pg_config
    /usr/pgsql-9.1/bin/pg_config

I tried adding the pg_config path to the `setup.cfg` file and building it using the source files I downloaded from their website (http://initd.org/psycopg/) and I get the following error message!

    Error: Unable to find &#39;pg_config&#39; file in &#39;/usr/pgsql-9.1/bin/&#39;


But it is actually THERE!!!

I am baffled by these errors. Can anyone help please?

By the way, I `sudo` all the commands. Also I am on RHEL 5.5.

pg_config executable not found

I&#39;m trying to build two functions using PyCrypto that accept two parameters: the message and the key, and then encrypt/decrypt the message.

I found several links on the web to help me out, but each one of them has flaws:

[This one at codekoala](http://www.codekoala.com/blog/2009/aes-encryption-python-using-pycrypto/) uses os.urandom, which is discouraged by PyCrypto.

Moreover, the key I give to the function is not guaranteed to have the exact length expected. What can I do to make that happen ?

Also, there are several modes, which one is recommended? I don&#39;t know what to use :/

Finally, what exactly is the IV? Can I provide a different IV for encrypting and decrypting, or will this return in a different result?

**Edit**: Removed the code part since it was not secure.

Encrypt &amp; Decrypt using PyCrypto AES 256

OpenSSL provides a popular (but insecure – see below!) command line interface for AES encryption:

    openssl aes-256-cbc -salt -in filename -out filename.enc

Python has support for AES in the shape of the PyCrypto package, but it only provides the tools. How to use Python/PyCrypto to decrypt files that have been encrypted using OpenSSL?

Notice
------
This question used to also concern encryption in Python using the same scheme. I have since removed that part to discourage anyone from using it. Do NOT encrypt any more data in this way, because it is NOT secure by today&#39;s standards. You should ONLY use decryption, for no other reasons than BACKWARD COMPATIBILITY, i.e. when you have no other choice. Want to encrypt? Use NaCl/libsodium if you possibly can.



How to decrypt OpenSSL AES-encrypted files in Python?

When I try to run app.py (Python 3.3, PyCrypto 2.6) my virtualenv keeps returning the error listed above. My import statement is just `from Crypto.Cipher import AES`. I looked for duplicates and you might say that there are some, but I tried the solutions (although most are not even solutions) and nothing worked.

You can see what the files are like for PyCrypto below:

![](http://i.imgur.com/ElrSw6L.png?1)

ImportError: No module named Crypto.Cipher

I just ran the following command:

    pip install -U steem

and the installation worked well until it failed to install `pycrypto`. 
Afterwards I did the

    pip install cryptography

command because I thought it was the missing package. 
So my question is, how I can install `steem` without the pycrypto-error (or the pycrypto-package in addition) and how to uninstall the cryptography-Package which I don&#39;t need. 
(I&#39;m using Windows 7 and Python 3)

    Requirement already up-to-date: python-dateutil in c:\users\***\appdata\lo
    cal\programs\python\python36\lib\site-packages (from dateparser-&gt;maya-&gt;steem)
    ...
    Installing collected packages: urllib3, idna, chardet, certifi, requests, pycryp
    to, funcy, w3lib, voluptuous, diff-match-patch, scrypt, prettytable, appdirs, la
    ngdetect, ruamel.yaml, humanize, tzlocal, regex, dateparser, pytzdata, pendulum,
    maya, ecdsa, pylibscrypt, ujson, toolz, steem
    Running setup.py install for pycrypto ... error
    Complete output from command c:\users\***\appdata\local\programs\pytho
    n\python36\python.exe -u -c &quot;import setuptools, tokenize;__file__=&#39;C:\\Users\\
    ***~1\\AppData\\Local\\Temp\\pip-build-k6flhu5k\\pycrypto\\setup.py&#39;;f=getattr(
    tokenize, &#39;open&#39;, open)(__file__);code=f.read().replace(&#39;\r\n&#39;, &#39;\n&#39;);f.close();
    exec(compile(code, __file__, &#39;exec&#39;))&quot; install --record C:\Users\***N~1\AppDat
    a\Local\Temp\pip-igpkll6u-record\install-record.txt --single-version-externally-
    managed --compile:
    running install
    running build
    running build_py
    ...
    building &#39;Crypto.Random.OSRNG.winrandom&#39; extension
    error: Microsoft Visual C++ 14.0 is required. Get it with &quot;Microsoft Visual
    C++ Build Tools&quot;: http://landinghub.visualstudio.com/visual-cpp-build-tools

    ----------------------------------------
    Command &quot;c:\users\***\appdata\local\programs\python\python36\python.exe -u
    -c &quot;import setuptools, tokenize;__file__=&#39;C:\\Users\\***N~1\\AppData\\Local\\
    Temp\\pip-build-k6flhu5k\\pycrypto\\setup.py&#39;;f=getattr(tokenize, &#39;open&#39;, open)(
    __file__);code=f.read().replace(&#39;\r\n&#39;, &#39;\n&#39;);f.close();exec(compile(code,   __fil
    e__, &#39;exec&#39;))&quot; install --record C:\Users\***N~1\AppData\Local\Temp\pip-igpkll6
    u-record\install-record.txt --single-version-externally-managed --compile&quot;   faile
    d with error code 1 in C:\Users\***N~1\AppData\Local\Temp\pip-build-    k6flhu5k\p
    ycrypto\

Pip error: Microsoft Visual C++ 14.0 is required

I have written code to generate public and private keys. It works great at Python 3.7 but it fails in Python 3.8. I don&#39;t know how it fails in the latest version. Help me with some solutions. 

Here&#39;s the Code:

    from Crypto.PublicKey import RSA


    def generate_keys():
        modulus_length = 1024
        key = RSA.generate(modulus_length)
        pub_key = key.publickey()
        private_key = key.exportKey()
        public_key = pub_key.exportKey()
        return private_key, public_key


    a = generate_keys()
    print(a)

Error in Python 3.8 version:

    Traceback (most recent call last):
      File &quot;temp.py&quot;, line 18, in &lt;module&gt;
        a = generate_keys()
      File &quot;temp.py&quot;, line 8, in generate_keys
        key = RSA.generate(modulus_length)
      File &quot;/home/paulsteven/.local/lib/python3.8/site-packages/Crypto/PublicKey/RSA.py&quot;, line 508, in generate
        obj = _RSA.generate_py(bits, rf, progress_func, e)    # TODO: Don&#39;t use legacy _RSA module
      File &quot;/home/paulsteven/.local/lib/python3.8/site-packages/Crypto/PublicKey/_RSA.py&quot;, line 50, in generate_py
        p = pubkey.getStrongPrime(bits&gt;&gt;1, obj.e, 1e-12, randfunc)
      File &quot;/home/paulsteven/.local/lib/python3.8/site-packages/Crypto/Util/number.py&quot;, line 282, in getStrongPrime
        X = getRandomRange (lower_bound, upper_bound, randfunc)
      File &quot;/home/paulsteven/.local/lib/python3.8/site-packages/Crypto/Util/number.py&quot;, line 123, in getRandomRange
        value = getRandomInteger(bits, randfunc)
      File &quot;/home/paulsteven/.local/lib/python3.8/site-packages/Crypto/Util/number.py&quot;, line 104, in getRandomInteger
        S = randfunc(N&gt;&gt;3)
      File &quot;/home/paulsteven/.local/lib/python3.8/site-packages/Crypto/Random/_UserFriendlyRNG.py&quot;, line 202, in read
        return self._singleton.read(bytes)
      File &quot;/home/paulsteven/.local/lib/python3.8/site-packages/Crypto/Random/_UserFriendlyRNG.py&quot;, line 178, in read
        return _UserFriendlyRNG.read(self, bytes)
      File &quot;/home/paulsteven/.local/lib/python3.8/site-packages/Crypto/Random/_UserFriendlyRNG.py&quot;, line 129, in read
        self._ec.collect()
      File &quot;/home/paulsteven/.local/lib/python3.8/site-packages/Crypto/Random/_UserFriendlyRNG.py&quot;, line 77, in collect
        t = time.clock()
    AttributeError: module &#39;time&#39; has no attribute &#39;clock&#39;





Content Type	Original Author	Original Content on Stackoverflow
Question	OJFord	View Question on Stackoverflow
Solution 1 - Python	Ned Batchelder	View Answer on Stackoverflow
Solution 2 - Python	Homer6	View Answer on Stackoverflow
Solution 3 - Python	Luka Lopusina	View Answer on Stackoverflow
Solution 4 - Python	babatunde adewole	View Answer on Stackoverflow

Installing PyCrypto on Ubuntu - fatal error on build

Python Problem Overview

Python Solutions

Solution 1 - Python

Solution 2 - Python

Solution 3 - Python

Solution 4 - Python

Cannot set Java breakpoint in Intellij IDEA

Decomposing tuples in function arguments

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