Python学习备忘

0.python_tips_index.md

#Python Tips

调用外部命令

detect function type

read large file

1.call_external_cmd.markdown

python脚本中执行命令行

os.system('cmd')

如果不想要结果输出，可以使用下面的代码

neveroutput = os.popen('your cmd').read()

2.detect_function_type.md

Detect function type

Credit: http://stackoverflow.com/a/624939

def is_function()
    return hasattr(foo, '__call__')

3.read_large_file.md

how to jump to a particular line in a huge text file?

Credit: http://stackoverflow.com/q/620367

Python doc: linecache

enumerate(fp) is a better solution.

http://stackoverflow.com/a/2081880

To Conclude: Use fileobject.readlines() or for line in fileobject as a quick solution for small files.
Use linecache for a more elegant solution, which will be quite fast for reading many files, possible repeatedly.
Take @Alok's advice and use enumerate() for files which might be very large, and won't fit into memory. Note that using this method might slow because the file is read sequentially.
Link: http://stackoverflow.com/a/2081861