[Tutor] updating a dictionary

[Alan Gauld]

On 19/02/15 21:19, Chris Stinemetz wrote:

> The dictionary format looks like:
>
> format = {'Cell': '','7':'','8':'','9':'','2':''}
>
> For each line read in I would simply like to check to see if a Cell
> key;value exists and if it does update the correct key==band(7,8,9,2)
> within the dictionary.
>
> If the Cell doesn't exist do the same thing as above only make sure to
> update the Cell key:value with it's value form the file so it can check to
> see if it exists later.

I'm not sure what the difference is here? If you update the dictionary 
or add a new key it will automatically  have that key going forward.

> There are duplicate Cell:values in the file so when
> there is a duplicate it will need to look at band to see what key:value to
> update.

I'm not sure what 'band' is? You have not mentioned it up until now.

> Below is what I have attempted thus far. I can provide sample data if
> needed.

I think a short same of your data would be useful, both input and output.


> import datetime
> import string
 > import pprint

You don't use string. Do you really need it? It's quite rarely
used  these days.
And you don't use pprint either. Do you plan on having a use
for it later?

> from datetime import datetime
>
> # Open a files for reading
> inFileOne = open('PRB_utilization.txt', "r")

You should get used to using the 'with' construct for file
handling, it's usually shorter and much more reliable.

> iDas = "DB"
> oDas = "D"
>
> suffix = (iDas,oDas)

suffix = ("DB","D")

would be shorter and more obvious, since you don't use the
single value variables anywhere in the code..

> dict = {'Cell': '','7':'','8':'','9':'','2':''}

Using dict as a name is a bad idea because it hides the
built in dict type conversion function.

> for line in inFileOne.readlines():

You don't need readlines() any more you can just
do:

for line in inFileOne:

>      index = line.rstrip("\n").split("\t")
>
>      cell = index[1]
>
>      if cell.endswith(suffix, 14, 16) is False:
>          eNb = cell[0:8]
>          sector = cell[10:11]
>          band = cell[9:10]
>          dl_prb_utl = index[60]
>          site = eNb + "_" + sector

I'll assume that's all OK since we can't see the data format.

>          if site in dict:
>              dict['Cell'] = site
>              dict[band] = dl_prb_utl
>          else:
>              dict['Cell'] = site
>              dict[band] = dl_prb_utl

Both 'if' and 'else' clauses do the same thing so there
is no point in doing a test. Just use:

            dict['Cell'] = site
            dict[band] = dl_prb_utl

> inFileOne.close();

You don't need this if you use the with... form.

Other than the minor tweaks I've suggested I'm not sure what your 
problem is? I think we need to see the data to understand the issue.

-- 
Alan G
Author of the Learn to Program web site
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