[Tutor] Dictionaries and aggregation

[Kent Johnson]

> However here's what I'm now trying to do:
>  
> 1)       Not have to rely on using awk at all.
>  
>  
> 2)       Create a dictionary with server names for keys e.g. server001,
> server002 etc and the aggregate of the request for that server as the value
> part of the pairing.
>  
>  
> I got this far with part 1)
>  
> lbstat = commands.getoutput("sudo ~/ZLBbalctl --action=cells")
> tmpLst = lbstat.split('\n')
>  
> rLst = []
> for i in tmpLst:
>     m = re.search(' server[0-9]+', i)
>     if m:
>         rLst.append(i)
>  
> for i in rLst:
>         print i, type(i)
>  
>   server001      alive 22.3%     6 requests/s 14527762 total <type 'str'>
>   server002      alive 23.5%     7 requests/s 14833265 total <type 'str'>
>   server003      alive 38.2%    14 requests/s 14872750 total <type 'str'>
>   server004      alive 15.6%     4 requests/s 15083443 total <type 'str'>
>   server001      alive 24.1%     8 requests/s 14473672 total <type 'str'>
>   server002      alive 23.2%     7 requests/s 14810866 total <type 'str'>
>   server003      alive 30.2%     8 requests/s 14918322 total <type 'str'>
>   server004      alive 22.1%     6 requests/s 15137847 total <type 'str'>
>  
> At this point I ran out of ideas and began to think that there must be
> something fundamentally wrong with my approach. Not least of my concerns was
> the fact that I needed integers and these were strings.

Don't get discouraged, you are on the right track! You had one big 
string that included some data you are interested in and some you don't 
want, you have converted that to a list of strings containing only the 
lines of interest. That is a good first step. Now you have to extract 
the data you want out of each line.

Use line.split() to split the text into fields by whitespace:
In [1]: line = '  server001      alive 22.3%     6 requests/s 14527762 
total'

In [2]: line.split()
Out[2]: ['server001', 'alive', '22.3%', '6', 'requests/s', '14527762', 
'total']

Indexing will pull out the field you want:
In [3]: line.split()[5]
Out[3]: '14527762'

It's still a string:
In [4]: type(line.split()[5])
Out[4]: <type 'str'>

Use int() to convert a string to an integer:
In [5]: int(line.split()[5])
Out[5]: 14527762

Then you have to figure out how to accumulate the values in a dictionary 
but get this much working first.

Kent