import fails when running python as script, but not in iPython? -

i have project structured such:

folder1        |        folder2              |              tests 

i have __init__.py in each folder. when in parent directory of folder1, run ipython , do

from folder1.folder2.tests.test1 import main main() 

everything works fine. when run

python folder1/folder2/tests/test1.py 

i importerror: no module named folder1.folder2.file1, import statement in test1

from folder1.folder2.file1 import class1 

confused - guessing path issue don't understand wrong code (many similar setups in other folders) , why still works in ipython , not python run script.

the module search path (python 3 docu) different , without script file:

interactive python interpreter

(goes both python , ipython)

$ python python 2.7.3 (default, dec 18 2014, 19:10:20)  [gcc 4.6.3] on linux2 type "help", "copyright", "credits" or "license" more information. >>> import sys >>> print(sys.path) ['', '/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/pymodules/python2.7/gtk-2.0', '/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/ubuntuone-client', '/usr/lib/python2.7/dist-packages/ubuntuone-control-panel', '/usr/lib/python2.7/dist-packages/ubuntuone-couch', '/usr/lib/python2.7/dist-packages/ubuntuone-installer', '/usr/lib/python2.7/dist-packages/ubuntuone-storage-protocol'] >>> 

note first entry being empty string. empty string relative path equivalent .. relative paths in module search path relative current working dir of interpreter process, current working dir invoked interpreter. (which in case happened root of project.)

executing script file

$ echo 'import sys' > /tmp/pathtest.py $ echo 'print(sys.path)' >> /tmp/pathtest.py  $ python /tmp/pathtest.py  ['/tmp', '/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/pymodules/python2.7/gtk-2.0', '/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/ubuntuone-client', '/usr/lib/python2.7/dist-packages/ubuntuone-control-panel', '/usr/lib/python2.7/dist-packages/ubuntuone-couch', '/usr/lib/python2.7/dist-packages/ubuntuone-installer', '/usr/lib/python2.7/dist-packages/ubuntuone-storage-protocol'] 

note here, first entry absolute path of directory containing script file passed argument.