大叔经验分享（11）python引入模块报错ImportError: No module named pandas numpy

python应用通常需要一些库，比如numpy、pandas等，安装也很简单，直接通过pip

# pip install numpy
Requirement already satisfied: numpy in /export/App/anaconda2/lib/python2.7/site-packages

# pip install pandasRequirement already satisfied: pandas in /export/App/anaconda2/lib/python2.7/site-packagesRequirement already satisfied: python-dateutil in /export/App/anaconda2/lib/python2.7/site-packages (from pandas)Requirement already satisfied: pytz>=2011k in /export/App/anaconda2/lib/python2.7/site-packages (from pandas)Requirement already satisfied: numpy>=1.7.0 in /export/App/anaconda2/lib/python2.7/site-packages (from pandas)Requirement already satisfied: six>=1.5 in /export/App/anaconda2/lib/python2.7/site-packages (from python-dateutil->pandas)

上边是已经安装好的提示信息，但是此时在python引入还是会报错

$ python
Python 2.6.6 (r266:84292, Aug 18 2016, 15:13:37)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-17)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import pandas as pd
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named pandas
>>>

这时通常的原因是因为你的机器上有两个版本的python（通常是系统自带一个，然后anaconda自带一个），一个版本下的python安装好了依赖，然后你在另一个版本下引入依赖

$ python -c 'import sys; print(sys.version_info)'
(2, 6, 6, 'final', 0)

$ python --version
Python 2.6.6

$ which python

以上可知当前python用的是2.6.6，但是依赖是安装在2.7（anaconda自带）下的，修改一下path即可

export PATH=/export/App/anaconda2/bin:$PATH

然后再引入即可

$ python
Python 2.7.13 |Anaconda 4.3.1 (64-bit)| (default, Dec 20 2016, 23:09:15)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-1)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
Anaconda is brought to you by Continuum Analytics.
Please check out: http://continuum.io/thanks and https://anaconda.org
>>> import pandas as pd
>>>

其实anaconda安装后会修改当前用户的~/.bashrc，修改path，指向自带python，其他用户可能会遇到上边的问题；

另外可以通过命令查看当前path有哪些版本python路径

$ whereis python