[Tutor] binary data struct module

[Kent Johnson]

John wrote:
> f2=file(infile,'rb')
> 
> Dfmt=['3i','13s','7i','2f','2i','2f','2i','i']  #format for binary 
> reading first bits
> 
> if f2:
>     print infile + ' has been opened'
>     #for ft in Dfmt:
>     #  print ft
>     a=(struct.unpack(ft,f2.read(struct.calcsize(ft))) for ft in Dfmt)
>     for ln in a: print ln

  however, how can I now assign variables based on the 'generator object'
> a? What exactly is this?

a is a generator which is an iterable object. Access to its values is 
through the iterator protocol such as the for loop you use.

> My question is, how can I now work with 'a' so that i can use the values?

Use a list comprehension instead of a generator expression:

a=[struct.unpack(ft,f2.read(struct.calcsize(ft))) for ft in Dfmt]

This creates a list instead of a generator object.

Kent