Python 实用宝典

Question 1

So it’s a new millennium; Apple has waved their hand; it’s now legal to include a Python interpreter in an iPhone (App Store) app.

How does one go about doing this? All the existing discussion (unsurprisingly) refers to jailbreaking. (Older question: Can I write native iPhone apps using Python)

My goal here isn’t to write a PyObjC app, but to write a regular ObjC app that runs Python as an embedded library. The Python code will then call back to native Cocoa code. It’s the “control logic is Python code” pattern.

Is there a guide to getting Python built in XCode, so that my iPhone app can link it? Preferably a stripped-down Python, since I won’t need 90% of the standard library.

I can probably figure out the threading and Python-extension API; I’ve done that on MacOS. But only using command-line compilers, not XCode.

Question 2

It doesn’t really matter how you build Python — you don’t need to build it in Xcode, for example — but what does matter is the product of that build.

Namely, you are going to need to build something like libPython.a that can be statically linked into your application. Once you have a .a, that can be added to the Xcode project for your application(s) and, from there, it’ll be linked and signed just like the rest of your app.

IIRC (it has been a while since I’ve built python by hand) the out-of-the-box python will build a libPython.a (and a bunch of other libraries), if you configure it correctly.

Of course, your second issue is going to be cross-compiling python for ARM from your 86 box. Python is an autoconf based project and autoconf is a pain in the butt for cross-compilation.

As you correctly state, making it small will be critical.

Not surprising, either, is that you aren’t the first person to want to do this, but not for iOS. Python has been squeezed into devices much less capable than those that run iOS. I found a thread with a bunch of links when googling about; it might be useful.

Also, you might want to join the pyobjc-dev list. While you aren’t targeting a PyObjC based application (which, btw, is a good idea — PyObjC has a long way to go before it’ll be iOS friendly), the PyObjC community has been discussing this and Ronald, of anyone, is probably the most knowledgeable person in this particular area. Note that PyObjC will have to solve the embedded Python on iOS problem prior to porting PyObjC. Their prerequisite is your requirement, as it were.

Question 3

I’ve put a very rough script up on github that fetches and builds python2.6.5 for iPhone and simulator.

http://github.com/cobbal/python-for-iphone

Work in progress

Somewhat depressing update nearly 2 years later: (copied from README on github)

This project never really got python running on the iPhone to my satisfaction, and I can’t recommend using it for any serious project at this stage.

Most notably missing is pyobjc support (which turns out to be much harder to port to iPhone since it relies on more platform-specific code)

Also missing is the ability to statically compile modules, (all are currently built as dylibs which works for development, but to my knowledge wouldn’t be allowed in the App Store)

At this point this project is mostly meant to be a starting point for anyone smarter than me who wants to and can tackle the above issues.

I really wish it were practical to write apps entirely in Python, but at this point it seems impossible.

Question 4

I also started such a project. It comes with its own simplified compile script so there is no need to mess around with autoconf to get your cross compiled static library. It is able to build a completely dependency-free static library of Python with some common modules. It should be easily extensible.

https://github.com/albertz/python-embedded/

Question 5

How does one create a Python friendly environment in Xcode 4, 5, 6 or 7?

Question 6

I figured it out! The steps make it look like it will take more effort than it actually does.

These instructions are for creating a project from scratch. If you have existing Python scripts that you wish to include in this project, you will obviously need to slightly deviate from these instructions.

If you find that these instructions no longer work or are unclear due to changes in Xcode updates, please let me know. I will make the necessary corrections.

Open Xcode. The instructions for either are the same.
In the menu bar, click “File” → “New” → “New Project…”.
Select “Other” in the left pane, then “External Build System” in the right page, and next click “Next”.
Enter the product name, organization name, or organization identifier.
For the “Build Tool” field, type in /usr/local/bin/python3 for Python 3 or /usr/bin/python for Python 2 and then click “Next”. Note that this assumes you have the symbolic link (that is setup by default) that resolves to the Python executable. If you are unsure as to where your Python executables are, enter either of these commands into Terminal: which python3 and which python.
Click “Next”.
Choose where to save it and click “Create”.
In the menu bar, click “File” → “New” → “New File…”.
Select “Other” under “OS X”.
Select “Empty” and click “Next”.
Navigate to the project folder (it will not work, otherwise), enter the name of the Python file (including the “.py” extension), and click “Create”.
In the menu bar, click “Product” → “Scheme” → “Edit Scheme…”.
Click “Run” in the left pane.
In the “Info” tab, click the “Executable” field and then click “Other…”.
Navigate to the executable from Step 5. You might need to use ⇧⌘G to type in the directory if it is hidden.
Select the executable and click “Choose”.
Uncheck “Debug executable”. If you skip this step, Xcode will try to debug the Python executable itself. I am unaware of a way to integrate an external debugging tool into Xcode.
Click the “+” icon under “Arguments Passed On Launch”. You might have to expand that section by clicking on the triangle pointing to the right.
Type in $(SRCROOT)/ (or $(SOURCE_ROOT)/) and then the name of the Python file you want to test. Remember, the Python program must be in the project folder. Otherwise, you will have to type out the full path (or relative path if it’s in a subfolder of the project folder) here. If there are spaces anywhere in the full path, you must include quotation marks at the beginning and end of this.
Click “Close”.

Note that if you open the “Utilities” panel, with the “Show the File inspector” tab active, the file type is automatically set to “Default – Python script”. Feel free to look through all the file type options it has, to gain an idea as to what all it is capable of doing. The method above can be applied to any interpreted language. As of right now, I have yet to figure out exactly how to get it to work with Java; then again, I haven’t done too much research. Surely there is some documentation floating around on the web about all of this.

Running without administrative privileges:

If you do not have administrative privileges or are not in the Developer group, you can still use Xcode for Python programming (but you still won’t be able to develop in languages that require compiling). Instead of using the play button, in the menu bar, click “Product” → “Perform Action” → “Run Without Building” or simply use the keyboard shortcut ^⌘R.

Other Notes:

To change the text encoding, line endings, and/or indentation settings, open the “Utilities” panel and click “Show the File inspector” tab active. There, you will find these settings.

For more information about Xcode’s build settings, there is no better source than this. I’d be interested in hearing from somebody who got this to work with unsupported compiled languages. This process should work for any other interpreted language. Just be sure to change Step 5 and Step 16 accordingly.

Question 7

I’ve created Xcode 4 templates to simplify the steps provided by Tyler.
The result is Python Project Template for Xcode 4.

Now what you need to do is download the templates, move it to /Developer/Library/Xcode/Templates/Project Templates/Mac/Others/ and then new a Python project with Xcode 4.

It still needs manual Scheme setup (you can refer to steps 12–20 provided by Tyler.)

Question 8

Procedure to get Python Working in XCode 7

Step 1: Setup your Project with a External Build System

Step 1.1: Edit the Project Scheme

Step 2: Specify Python as the executable for the project (shift-command-g) the path should be /usr/bin/python

Step 3: Specify your custom working directory

Step 4: Specify your command line arguments to be the name of your python file. (in this example “test.py”)

Step 5: Thankfully thats it!

(debugging can’t be added until OSX supports a python debugger?)

Question 9

You should try PyDev plug in for Eclipse. I tried alot of editors/IDE’s to use with python, but the only one i liked the most is the PyDev plugin for Eclipse. It has code completion, debugger and many other nice features. Plus both are free.

Question 10

Another way, which I’ve been using for awhile in XCode3:

See steps 1-15 above.

Choose /bin/bash as your executable
For the “Debugger” field, select “None”.
In the “Arguments” tab, click the “Base Expansions On” field and select the target you created earlier.
Click the “+” icon under “Arguments Passed On Launch”. You may have to expand that section by clicking on the triangle pointing to the right.
Type in “-l”. This will tell bash to use your login environment (PYTHONPATH, etc..)
Do step #19 again.
Type in “-c ‘$(SOURCE_ROOT)/.py'”
Click “OK”.
Start coding.

The nice thing about this way is it will use the same environment to develop in that you would use to run in outside of XCode (as setup from your bash .profile).

It’s also generic enough to let you develop/run any type of file, not just python.

Question 11

This Technical Note TN2328 from Apple Developer Library helped me a lot about Changes To Embedding Python Using Xcode 5.0.

Question 12

This thread is old, but to chime in for Xcode Version 8.3.3, Tyler Crompton’s method in the accepted answer still works (some of the names are very slightly different, but not enough to matter).

2 points where I struggled slightly:

Step 16: If the python executable you want is greyed out, right click it and select quick look. Then close the quick look window, and it should now be selectable.

Step 19: If this isn’t working for you, you can enter the name of just the python file in the Arguments tab, and then enter the project root directory explicitly in the Options tab under Working Directory–check the “Use custom working directory” box, and type in your project root directory in the field below it.

Question 13

Try Editra It’s free, has a lot of cool features and plug-ins, it runs on most platforms, and it is written in Python. I use it for all my non-XCode development at home and on Windows/Linux at work.

Question 14

I want to install Lxml so I can then install Scrapy.

When I updated my Mac today it wouldn’t let me reinstall lxml, I get the following error:

In file included from src/lxml/lxml.etree.c:314:
/private/tmp/pip_build_root/lxml/src/lxml/includes/etree_defs.h:9:10: fatal error: 'libxml/xmlversion.h' file not found
#include "libxml/xmlversion.h"
         ^
1 error generated.
error: command 'cc' failed with exit status 1

I have tried using brew to install libxml2 and libxslt, both installed fine but I still cannot install lxml.

Last time I was installing I needed to enable the developer tools on Xcode but since its updated to Xcode 5 it doesnt give me that option anymore.

Does anyone know what I need to do?

Question 15

You should install or upgrade the commandline tool for xcode. Try this in a terminal:

xcode-select --install

Question 16

I solved this issue on Yosemite by both installing and linking libxml2 and libxslt through brew:

brew install libxml2
brew install libxslt
brew link libxml2 --force
brew link libxslt --force

If you have solved the problem using this method but it pops up again at a later time, you might need to run this before the four lines above:

brew unlink libxml2
brew unlink libxslt

If you are having permission errors with Homebrew, especially on El Capitan, this is a helpful document. In essence, regardless of OS X version, try running:

sudo chown -R $(whoami):admin /usr/local

Question 17

You may solve your problem by running this on the commandline:

 STATIC_DEPS=true pip install lxml

It sure helped me. Explanations on docs

Question 18

I tried most of the solutions above, but none of them worked for me. I’m running Yosemite 10.10, the only solution that worked for me was to type this in the terminal:

sudo CPATH=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/libxml2 CFLAGS=-Qunused-arguments CPPFLAGS=-Qunused-arguments pip install lxml

EDIT: If you are using virtualenv, the sudo in beginning is not needed.

Question 19

This has been bothering me as well for a while. I don’t know the internals enough about python distutils etc, but the include path here is wrong. I made the following ugly hack to hold me over until the python lxml people can do the proper fix.

sudo ln -s  /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/libxml2/libxml/ /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/libxml

Question 20

Installing globally… OS X 10.9.2

xcode-select --install
sudo easy_install pip
sudo CPATH=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/libxml2 CFLAGS=-Qunused-arguments CPPFLAGS=-Qunused-arguments pip install lxml

Question 21

instalation instructions on http://lxml.de/installation.html explain:

To speed up the build in test environments, e.g. on a continuous integration server, disable the C compiler optimisations by setting the CFLAGS environment variable:

CFLAGS="-O0" pip install lxml

Question 22

None of the above worked for me on 10.9.2, as compilation bails out with following error:

clang: error: unknown argument: '-mno-fused-madd'

Which actually lead to cleanest solution (see more details in [1]):

export CFLAGS=-Qunused-arguments
export CPPFLAGS=-Qunused-arguments

pip install lxml

or following if installing globally

sudo pip install lxml

[1] clang error: unknown argument: ‘-mno-fused-madd’ (python package installation failure)

Question 23

xcode-select --install
sudo easy_install pip
sudo pip install lxml

Question 24

I solved this issue on Yosemite by running the following commands:

xcode-select install #this may take several minutes.
pip install lxml

Question 25

With homebrew, libxml2 is hidden to not interfere with the system libxml2, so pip must be helped a little in order to find it.

With bash:

LDFLAGS=-L`brew --prefix libxml2`/lib CPPFLAGS=-I`brew --prefix libxml2`/include/libxml2 pip install --user lxml

With fish:

env LDFLAGS=-L(brew --prefix libxml2)/lib CPPFLAGS=-I(brew --prefix libxml2)/include/libxml2 pip install --user lxml

Question 26

OSX 10.9.2

sudo env ARCHFLAGS=-Wno-error=unused-command-line-argument-hard-error-in-future STATIC_DEPS=true pip install lxml

Question 27

I tried all the answers on this page, none of them worked for me. I’m running OS X Version 10.9.2

But this definitely works….like a charm:

ARCHFLAGS=-Wno-error=unused-command-line-argument-hard-error-in-future pip install lxml

Question 28

Unfortunately xcode-select --install did not work for me as I already had the latest version.

It’s very strange but I solved the issue by opening XCode and accepting the Terms & Conditions. Re-running pip install lxml returned no errors after.

Question 29

After successful install from pip (lxml 3.6.4) I was getting an error when importing the lxml.etree module.

I was searching endlessly to install this as a requisite for scrapy, and tried all the options, but finally this worked for me (mac osx 10.11 python 2.7):

$ STATIC_DEPS=true sudo easy_install-2.7 "lxml==2.3.5"

The older version of lxml seem to work with etree module.

Pip can often ignore the specified version of a package, for example when you have the newer version in the pip cache, thus the easy_install. The '-2.7' option is for python version, omit this if you are installing for python 3.x.

Question 30

In my case, I must shutdown Kaspersky Antivirus before installing lxml by:

pip install lxml

Question 31

I am using OSX 10.9.2 and I get the same error.

Installation of the XCode command line tools does not help for this particular version of OSX.

I think a better approach to fix this is to install with the following command:

$ CPATH=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/libxml2 pip install lxml

This is similar to jdkoftinoff’ fix, but does not alter your system in a permanent way.

Question 32

I met the same question and after days of working I resolved this problem on my OS X 10.9.4, with Python 3.4.1.

Here’s my solution,

According to installing lxml from lxml.de,

A macport of lxml is available. Try something like port install py25-lxml

If you do not have MacPort, install it from MacPort.org. It’s quite easy. You may also need a compiler, to install XCode compiling tools, use xcode-select --install

Firstly I updated my port to the latest version via sudo port selfupdate,

Then I just type sudo port install libxml2 and several minutes later you should see libxml2 installed successfully. Probably you may also need libxslt to install lxml. To install libxslt, use:sudo port install libxslt.

Now, just type pip install lxml, it should work fine.

Question 33

before compiling add the path that to xmlversion.h into your environment.

$ set INCLUDE=$INCLUDE:/private/tmp/pip_build_root/lxml/src/lxml/

But make sure the path I’ve provided has the xmlversion.h file located inside. Then,

$ python setup.py install

Question 34

pip did not work for me. I went to https://pypi.python.org/pypi/lxml/2.3 and downloaded the macosx .egg file:

https://pypi.python.org/packages/2.7/l/lxml/lxml-2.3-py2.7-macosx-10.6-intel.egg#md5=52322e4698d68800c6b6aedb0dbe5f34

Then used command line easy_install to install the .egg file.

Question 35

This post links to a solution that worked for me Python3, lxml and “Symbol not found: _lzma_auto_decoder” on Mac OS X 10.9

hth

Question 36

After much tearing of the hair and gnashing of the teeth, I uninstalled xcode with pip and ran:

easy_install lxml

And all was well.

Question 37

Try:

% STATIC_DEPS=true pip install lxml

Or:

% STATIC_DEPS=true sudo pip install lxml

It works!

问题：将Python嵌入iPhone应用程序

回答 0

回答 1

回答 2

问题：Xcode 4+中的Python？

回答 0

在没有管理特权的情况下运行：

其他说明：

Running without administrative privileges:

Other Notes:

回答 1

回答 2

回答 3

回答 4

回答 5

回答 6

回答 7

问题：无法在Mac OS X 10.9上安装Lxml

回答 0

回答 1

回答 2

回答 3

回答 4

回答 5

回答 6

回答 7

回答 8

回答 9

回答 10

回答 11

回答 12

回答 13

回答 14

回答 15

回答 16

回答 17

回答 18

回答 19

回答 20

回答 21

回答 22

有趣好用的Python教程