Python-非常奇怪的sys.path行為

Question

sys.path [0]的條目是'/usr/lib/python2.7/dist-packages/wx-2.8-gtk2-unicode' 。 Python文檔說這應該是腳本的工作目錄。 知道會發生什么嗎？

當我從交互式解釋器運行Python並import sys; print sys.path[0]; import sys; print sys.path[0]; 它打印''似乎是正確的”。

但是，當從perl腳本調用我的Python腳本時，我得到了sys.path[0]的上述條目。

其他資訊：

• 我正在運行Python 2.7。
• 我使用的是Ubuntu 11.10 64位。
• 我的工作目錄應該是/ mnt / galaxyData / custom / MSG_toy
• 它調用的perl腳本和python腳本位於/ mnt / galaxyData / custom / MSG_toy / msg中（如果重要，則該msg目錄是符號鏈接）

這是sys.path上的所有內容：

['/usr/lib/python2.7/dist-packages/wx-2.8-gtk2-unicode',
 '/mnt/galaxyData/custom/msg',
 '/usr/local/lib/python2.7/dist-packages/bx_python-0.7.1-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/pip-1.0.2-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/amqplib-1.0.2-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/BeautifulSoup-3.2.0-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/boto-2.1.1-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/Fabric-1.3.2-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/ssh-1.7.9-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/ipython-0.11-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/Logbook-0.3-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/lxml-2.3.2-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/Mako-0.5.0-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/MarkupSafe-0.15-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/nose-1.1.2-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/numpy-1.6.1-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/Paste-1.7.5.1-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/PasteScript-1.7.5-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/PasteDeploy-1.5.0-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/python_cjson-1.0.5-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/pyOpenSSL-0.13-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/PyYAML-3.10-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/Routes-1.12.3-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/simplejson-2.2.1-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/Sphinx-1.1.2-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/docutils-0.8.1-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/Jinja2-2.6-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/Pygments-1.4-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/WebHelpers-1.3-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/WebOb-1.2b2-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/xlrd-0.7.1-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/Cython-0.15.1-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/Pyrex-0.9.9-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/virtualenv-1.6.4-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/tornado-2.1.1-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/Twisted-11.0.0-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/biopython-1.58-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/celery-2.4.2-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/pysam-0.5-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/python_dateutil-1.5-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/kombu-1.4.3-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/anyjson-0.3.1-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/DendroPy-3.9.0-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/HTSeq-0.5.3p3-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/networkx-1.5-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/pandas-0.5.0-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/pygr-0.8.2-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/pysparse-1.2_dev-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/rpy2-2.2.4dev_20111114-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/rpy2_bioconductor_extensions-0.2.5_dev-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/scikits.learn-0.8.1-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/scikits.statsmodels-0.3.1-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/scipy-0.10.0-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/sympy-0.7.1-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/CouchDB-0.8-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/h5py-2.0.1-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/MySQL_python-1.2.3-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/pymongo-2.0.1-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/pysqlite-2.6.3-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/psycopg2-2.4.2-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/SQLAlchemy-0.7.3-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/gnuplot_py-1.8-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/PIL-1.1.7-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/pydot-1.0.25-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/pyparsing-1.5.6-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/pygooglechart-0.3.0-py2.7.egg',
 '/usr/local/lib/python2.7/dist-packages/reportlab-2.5-py2.7-linux-x86_64.egg',
 '/usr/local/lib/python2.7/dist-packages/bcbio_nextgen-0.3a-py2.7.egg',
 '/mnt/galaxyData/custom/bin/python_libs',
 '/mnt/galaxyData/custom/MSG_toy',
 '/usr/lib/python2.7',
 '/usr/lib/python2.7/plat-linux2',
 '/usr/lib/python2.7/lib-tk',
 '/usr/lib/python2.7/lib-old',
 '/usr/lib/python2.7/lib-dynload',
 '/usr/local/lib/python2.7/dist-packages',
 '/usr/lib/python2.7/dist-packages',
 '/usr/lib/python2.7/dist-packages/PIL',
 '/usr/lib/python2.7/dist-packages/gst-0.10',
 '/usr/lib/python2.7/dist-packages/gtk-2.0',
 '/usr/lib/pymodules/python2.7',
 '/usr/lib/python2.7/dist-packages/ubuntu-sso-client',
 '/usr/lib/python2.7/dist-packages/wx-2.8-gtk2-unicode']

Answer 1

應該這樣做：

import os; print(os.path.dirname(__file__))

信任@AndiDog。

編輯：還請注意__file__的可用性和價值的文檔（ 此處和此處 ）中的提示：

預定義（可寫）屬性：__name__是模塊的名稱； __doc__是模塊的文檔字符串，如果不可用，則為None。 __file__是從中加載模塊的文件的路徑名（如果它是從文件加載的）。 靜態鏈接到解釋器的C模塊不提供__file__屬性。 對於從共享庫動態加載的擴展模塊，它是共享庫文件的路徑名。

__file__設置為模塊加載器提供的名稱。 如果加載程序不提供文件名信息，則此變量設置為None。