通过引用将编码传递给功能的位编码列表

Question

I seem to have an issue with a Manager.dict() that gets passed to a list of functions (within a sub process) as when I modify it within the function, the new value isn't available outside. I create my list of functions like this:

gwfuncs = [reboot, flush_macs, flush_cache, new_gw, revert_gw, send_log]
gw_func_dict = dict((chr(2**i), gwfuncs[i]) for i in xrange(0,min(len(gwfuncs),8)))

and then call it like this:

for bit in gw_func_dict.keys():
    if gwupdate & ord(bit) == ord(bit):
        gw_func_dict[bit](fh, maclist)

Now assume we're talking about flush_macs() , whatever I do in the function to maclist, doesn't seem to be affecting the maclist outside of my function - why is this? How can I modify it the way that my changes are available outside?

Answer 1

== has higher precedence than & , so your if statement really acts like this:

if gwupdate & (ord(bit) == ord(bit)):

Add some parentheses and it'll work:

if (gwupdate & ord(bit)) == ord(bit):

Also, you can simplify your code a little:

gw_func_dict = dict((chr(2**i), func) for i, func in enumerate(gwfuncs[:8]))

And if you're using Python 2.7+:

gw_func_dict = {chr(2**i): func for i, func in enumerate(gwfuncs[:8])}

Also, iterating over a dictionary iterates over its keys by default, so you can remove .keys() from your for loop:

for bit in gw_func_dict: