[Tutor] Looking up a value in a dictionary from user input problem

[vince spicer]

On Thu, Aug 6, 2009 at 3:42 PM, vince spicer <vinces1979 at gmail.com> wrote:

>
>
> On Thu, Aug 6, 2009 at 3:18 PM, chase pettet <chase.mp at gmail.com> wrote:
>
>> I am trying to write a script to work our LVS implementation.  I want to
>> be able to have  user do something like this "./script SITE SERVER" and have
>> the script look up the ip value of the site on that server and issue the
>> command to pull the status from LVS.  I am almost there but for some reason
>> when I try to pass the site parameter dynamically (the name of the
>> dictionary) I keep getting errors about value type.  I have two example that
>> work where the dictionary name is hard coded to to speak in the script, and
>> the value I want to pull is dynamic using sys.argv[1], and one where I'm
>> trying to pass the dictionary name and it does not work.  I tried to slim
>> thse examples down, so hopefully they are helpful:
>>
>> works #1...
>>
>> ./script.py t
>>
>> #!/usr/bin/env python
>> site = {"l":"10.1.1.1", "t":"10.1.1.2", "x":"10.1.1.3", "s1":"10.1.1.4",
>> "s2":"10.1.1.5", "s3":"10.1.1.6"}
>>
>> def runBash(cmd):
>>   p = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE)
>>   out = p.stdout.read().strip()
>>   return out
>>
>> class LVS_Site:
>>   def show(self, site):
>>     showsite = "ipvsadm -L -t %s:443" % (site)
>>     showsiteresult = runBash(showsite)
>>     return showsiteresult
>>
>> a = LVS_Site()
>> b = site["%s" % (sys.argv[1])]
>> c = a.show(b)
>> print ""
>> print ""
>> print ""
>> print c
>>
>> works #2...
>>
>> ./script.py t
>>
>> #!/usr/bin/env python
>> site = {"l":"10.1.1.1", "t":"10.1.1.2", "x":"10.1.1.3", "s1":"10.1.1.4",
>> "s2":"10.1.1.5", "s3":"10.1.1.6"}
>>
>> def runBash(cmd):
>>   p = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE)
>>   out = p.stdout.read().strip()
>>   return out
>>
>> class LVS_Site:
>>   def show(self, site):
>>     showsite = "ipvsadm -L -t %s:443" % (site)
>>     showsiteresult = runBash(showsite)
>>     return showsiteresult
>>
>> a = LVS_Site()
>> z = site
>> b = z["%s" % (sys.argv[1])]
>> c = a.show(b)
>> print ""
>> print ""
>> print ""
>> print c
>>
>>
>> Not working...
>>
>> ./script.py t site
>>
>> #!/usr/bin/env python
>> site = {"l":"10.1.1.1", "t":"10.1.1.2", "x":"10.1.1.3", "s1":"10.1.1.4",
>> "s2":"10.1.1.5", "s3":"10.1.1.6"}
>>
>> def runBash(cmd):
>>   p = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE)
>>   out = p.stdout.read().strip()
>>   return out
>>
>> class LVS_Site:
>>   def show(self, site):
>>     showsite = "ipvsadm -L -t %s:443" % (site)
>>     showsiteresult = runBash(showsite)
>>     return showsiteresult
>>
>> a = LVS_Site()
>> z = sys.argv[2]
>> b = b["%s" % (sys.argv[1])]
>> c = a.show(b)
>> print ""
>> print ""
>> print ""
>> print c
>>
>> Error:
>>
>> Traceback (most recent call last):
>>   File "./python2.py", line 22, in ?
>>     b = z["%s" % (sys.argv[1])]
>> TypeError: string indices must be integers
>>
>>
>> I don't understand why the third one does not work. Thanks for any help!
>>
>> _______________________________________________
>> Tutor maillist  -  Tutor at python.org
>> http://mail.python.org/mailman/listinfo/tutor
>>
>>
> In your code
>
> z = sys.argv[2] which is a string
>
> think you want
>
> b = site[z]
>

or even better

b =  site.get(z, None)
if b is None:
    print "Not Found"
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