Python 实用宝典

Question 1

OS X (Mavericks) has Python 2.7 stock installed. But I do all my own personal Python stuff with 3.3. I just flushed my 3.3.2 install and installed the new 3.3.3. So I need to install pyserial again. I can do it the way I’ve done it before, which is:

Download pyserial from pypi
untar pyserial.tgz
cd pyserial
python3 setup.py install

But I’d like to do like the cool kids do, and just do something like pip3 install pyserial. But it’s not clear how I get to that point. And just that point. Not interested (unless I have to be) in virtualenv yet.

Question 2

UPDATE: This is no longer necessary with Python3.4. It installs pip3 as part of the stock install.

I ended up posting this same question on the python mailing list, and got the following answer:

# download and install setuptools
curl -O https://bootstrap.pypa.io/ez_setup.py
python3 ez_setup.py
# download and install pip
curl -O https://bootstrap.pypa.io/get-pip.py
python3 get-pip.py

Which solved my question perfectly. After adding the following for my own:

cd /usr/local/bin
ln -s ../../../Library/Frameworks/Python.framework/Versions/3.3/bin/pip pip

So that I could run pip directly, I was able to:

# use pip to install
pip install pyserial

or:

# Don't want it?
pip uninstall pyserial

Question 3

I had to go through this process myself and chose a different way that I think is better in the long run.

I installed homebrew

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

then:

brew doctor

The last step gives you some warnings and errors that you have to resolve. One of those will be to download and install the Mac OS X command-line tools.

then:

brew install python3

This gave me python3 and pip3 in my path.

pieter$ which pip3 python3
/usr/local/bin/pip3
/usr/local/bin/python3

Question 4

Install Python3 on mac

1. brew install python3
2. curl https://bootstrap.pypa.io/get-pip.py | python3
3. python3

Use pip3 to install modules

1. pip3 install ipython
2. python3 -m IPython

:)

Question 5

Plus: when you install requests with python3, the command is:

pip3 install requests

not

pip install requests

Question 6

brew install python3
create alias in your shell profile
- eg. alias pip3="python3 -m pip" in my .zshrc

➜ ~ pip3 –version

pip 9.0.1 from /usr/local/lib/python3.6/site-packages (python 3.6)

Question 7

Here is my simple solution:

If you have python2 and python3 both installed in your system, the pip upgrade will point to python2 by default. Hence, we must specify the version of python(python3) and use the below command:

python3 -m pip install --upgrade pip

This command will uninstall the previously installed pip and install the new version- upgrading your pip.

This will save memory and declutter your system.

Image – How the upgrading of pip in Python3 works on MacOS

Question 8

To use Python EasyInstall (which is what I think you’re wanting to use), is super easy!

sudo easy_install pip

so then with pip to install Pyserial you would do:

pip install pyserial

Question 9

Also, it’s worth to mention that Max OSX/macOS users can just use Homebrew to install pip3.

$> brew update
$> brew install python3
$> pip3 --version
pip 9.0.1 from /usr/local/lib/python3.6/site-packages (python 3.6)

Question 10

On Mac OS X Mojave python stands for python of version 2.7 and python3 for python of version 3. The same is pip and pip3. So, to upgrade pip for python 3 do this:

~$ sudo pip3 install --upgrade pip

Question 11

On MacOS 10.12

download pip: pip as get-pip.py

download python3: python3

install python3
open terminal: python3 get-pip.py
pip3 is available

Question 12

pip is installed automatically with python2 using brew:

brew install python3
pip3 --version

Question 13

simply run following on terminal if you don’t have pip installed on your mac.

sudo easy_install pip

download python 3 here: python3

once you’re done with these 2 steps, make sure to run the following to verify whether you’ve installed them successfully.

python3 --version
pip3 --version

Question 14

For a fresh new Mac, you need to follow below steps:-

Make sure you have installed Xcode
sudo easy_install pip
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
brew doctor
brew doctor
brew install python3

And you are done, just type python3 on terminal and you will see python 3 installed.

Question 15

I had the same problem with python3 and pip3. Decision: solving all conflicts with links and other stuff when do

brew doctor

After that

brew reinstall python3

Question 16

I’ve implemented a BloomFilter in python 3.3, and got different results every session. Drilling down this weird behavior got me to the internal hash() function – it returns different hash values for the same string every session.

Example:

>>> hash("235")
-310569535015251310

—– opening a new python console —–

>>> hash("235")
-1900164331622581997

Why is this happening? Why is this useful?

Question 17

Python uses a random hash seed to prevent attackers from tar-pitting your application by sending you keys designed to collide. See the original vulnerability disclosure. By offsetting the hash with a random seed (set once at startup) attackers can no longer predict what keys will collide.

You can set a fixed seed or disable the feature by setting the PYTHONHASHSEED environment variable; the default is random but you can set it to a fixed positive integer value, with 0 disabling the feature altogether.

Python versions 2.7 and 3.2 have the feature disabled by default (use the -R switch or set PYTHONHASHSEED=random to enable it); it is enabled by default in Python 3.3 and up.

If you were relying on the order of keys in a Python set, then don’t. Python uses a hash table to implement these types and their order depends on the insertion and deletion history as well as the random hash seed. Note that in Python 3.5 and older, this applies to dictionaries, too.

Also see the object.__hash__() special method documentation:

Note: By default, the __hash__() values of str, bytes and datetime objects are “salted” with an unpredictable random value. Although they remain constant within an individual Python process, they are not predictable between repeated invocations of Python.

This is intended to provide protection against a denial-of-service caused by carefully-chosen inputs that exploit the worst case performance of a dict insertion, O(n^2) complexity. See http://www.ocert.org/advisories/ocert-2011-003.html for details.

Changing hash values affects the iteration order of dicts, sets and other mappings. Python has never made guarantees about this ordering (and it typically varies between 32-bit and 64-bit builds).

See also PYTHONHASHSEED.

If you need a stable hash implementation, you probably want to look at the hashlib module; this implements cryptographic hash functions. The pybloom project uses this approach.

Since the offset consists of a prefix and a suffix (start value and final XORed value, respectively) you cannot just store the offset, unfortunately. On the plus side, this does mean that attackers cannot easily determine the offset with timing attacks either.

Question 18

Hash randomisation is turned on by default in Python 3. This is a security feature:

Hash randomization is intended to provide protection against a denial-of-service caused by carefully-chosen inputs that exploit the worst case performance of a dict construction

In previous versions from 2.6.8, you could switch it on at the command line with -R, or the PYTHONHASHSEED environment option.

You can switch it off by setting PYTHONHASHSEED to zero.

Question 19

hash() is a Python built-in function and use it to calculate a hash value for object, not for string or num.

You can see the detail in this page: https://docs.python.org/3.3/library/functions.html#hash.

and hash() values comes from the object’s __hash__ method. The doc says the followings:

By default, the hash() values of str, bytes and datetime objects are “salted” with an unpredictable random value. Although they remain constant within an individual Python process, they are not predictable between repeated invocations of Python.

That’s why your have diffent hash value for the same string in different console.

What you implement is not a good way.

When you want to calculate a string hash value, just use hashlib

hash() is aim to get a object hash value, not a stirng.

Question 20

I’m having troubles with installing packages in Python 3.

I have always installed packages with setup.py install. But now, when I try to install the ansicolors package I get:

importerror “No Module named Setuptools”

I have no idea what to do because I didn’t have setuptools installed in the past. Still, I was able to install many packages with setup.py install without setuptools. Why should I get setuptools now?

I can’t even install setuptools because I have Python 3.3 and setuptools doesn’t support Python 3.

Why doesn’t my install command work anymore?

Question 21

Your setup.py file needs setuptools. Some Python packages used to use distutils for distribution, but most now use setuptools, a more complete package. Here is a question about the differences between them.

To install setuptools on Debian:

sudo apt-get install python3-setuptools

For an older version of Python (Python 2.x):

sudo apt-get install python-setuptools

Question 22

EDIT: Official setuptools dox page:

If you have Python 2 >=2.7.9 or Python 3 >=3.4 installed from python.org, you will already have pip and setuptools, but will need to upgrade to the latest version:

On Linux or OS X:
pip install -U pip setuptools 
On Windows:
python -m pip install -U pip setuptools

Therefore the rest of this post is probably obsolete (e.g. some links don’t work).

Distribute – is a setuptools fork which “offers Python 3 support”. Installation instructions for distribute(setuptools) + pip:

curl -O http://python-distribute.org/distribute_setup.py
python distribute_setup.py
easy_install pip

Similar issue here.

UPDATE: Distribute seems to be obsolete, i.e. merged into Setuptools: Distribute is a deprecated fork of the Setuptools project. Since the Setuptools 0.7 release, Setuptools and Distribute have merged and Distribute is no longer being maintained. All ongoing effort should reference the Setuptools project and the Setuptools documentation.

You may try with instructions found on setuptools pypi page (I haven’t tested this, sorry :( ):

wget https://bitbucket.org/pypa/setuptools/raw/bootstrap/ez_setup.py -O - | python
easy_install pip

Question 23

I was doing this inside a virtualenv on Oracle Linux 6.4 using python-2.6 so the apt-based solutions weren’t an option for me, nor were the python-2.7 ideas. My fix was to upgrade my version of setuptools that had been installed by virtualenv:

pip install --upgrade setuptools

After that, I was able to install packages into the virtualenv. I know this question has already had an answer selected but I hope this answer will help others in my situation.

Question 24

pip uninstall setuptools

and then:

pip install setuptools

This works for me and fix my issue.

Question 25

The distribute package provides a Python 3-compatible version of setuptools: http://pypi.python.org/pypi/distribute

Also, use pip to install the modules. It automatically finds dependencies and installs them for you.

It works just fine for me with your package:

[~] pip --version                                                              
pip 1.2.1 from /usr/lib/python3.3/site-packages (python 3.3)
[~] sudo pip install ansicolors                                                
Downloading/unpacking ansicolors
  Downloading ansicolors-1.0.2.tar.gz
  Running setup.py egg_info for package ansicolors

Installing collected packages: ansicolors
  Running setup.py install for ansicolors

Successfully installed ansicolors
Cleaning up...
[~]

Question 26

Windows 7:

I have given a complete solution here for python selenium webdriver

1. Setup easy install (windows - simplified)
    a. download ez.setup.py (https://bootstrap.pypa.io/ez_setup.py) from 'https://pypi.python.org/pypi/setuptools'
    b. move ez.setup.py to C:\Python27\
    c. open cmd prompt
    d. cd C:\Python27\
    e. C:\Python27\python.exe ez.setup.py install

Question 27

The PyPA recommended tool for installing and managing Python packages is pip. pip is included with Python 3.4 (PEP 453), but for older versions here’s how to install it (on Windows):

Download https://bootstrap.pypa.io/get-pip.py

>c:\Python33\python.exe get-pip.py
Downloading/unpacking pip
Downloading/unpacking setuptools
Installing collected packages: pip, setuptools
Successfully installed pip setuptools
Cleaning up...

>c:\Python33\Scripts\pip.exe install pymysql
Downloading/unpacking pymysql
Installing collected packages: pymysql
Successfully installed pymysql
Cleaning up...

Question 28

A few years ago I inherited a python (2.7.1) project running under Django-1.2.3 and now was asked to enhance it with QR possibilities. Got the same problem and did not find pip or apt-get either. So I solved it in a totally different but easy way. I /bin/vi-ed the setup.py and changed the line “from setuptools import setup” into: “from distutils.core import setup” That did it for me, so I thought I should post this for other users running old pythons. Regards, Roger Vermeir

Python 实用宝典

标签归档：python-3.3

如何在Mac OS X上为Python 3安装pip？

问题：如何在Mac OS X上为Python 3安装pip？

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

Python 3.3中的哈希函数在会话之间返回不同的结果

问题：Python 3.3中的哈希函数在会话之间返回不同的结果

回答 0

回答 1

回答 2

Python 3：ImportError“没有名为Setuptools的模块”

问题：Python 3：ImportError“没有名为Setuptools的模块”

回答 0

回答 1

回答 2

回答 3

回答 4

回答 5

回答 6

回答 7

有趣好用的Python教程