Whining about "struct"
tjreedy at udel.edu
Thu Oct 14 06:49:13 CEST 2010
On 10/14/2010 12:30 AM, Tim Roberts wrote:
> I have a bad memory. I admit it. Because of that, the Python "help"
> system is invaluable to me. Up through Python 2.5, I could get a quick
> reference to the format specifiers for the struct module via
> import struct; help(struct)
> I used that a LOT.
> But in Python 2.6, the struct module moved from Python code to C code, and
> that helpful help string was removed.
> Is that still gone in Python 3.1? What are the chances of reinstating that
> helpful chart?
With 3.1, help(struct) includes the following:
The optional first format char indicates byte order, size and
@: native order, size & alignment (default)
=: native order, std. size & alignment
<: little-endian, std. size & alignment
>: big-endian, std. size & alignment
!: same as >
The remaining chars indicate types of args and must match exactly;
these can be preceded by a decimal repeat count:
x: pad byte (no data); c:char; b:signed byte; B:unsigned byte;
?: _Bool (requires C99; if not available, char is used instead)
h:short; H:unsigned short; i:int; I:unsigned int;
l:long; L:unsigned long; f:float; d:double.
Special cases (preceding decimal count indicates length):
s:string (array of char); p: pascal string (with count byte).
Special case (only available in native format):
P:an integer type that is wide enough to hold a pointer.
Special case (not in native mode unless 'long long' in platform C):
q:long long; Q:unsigned long long
Whitespace between formats is ignored.
If this does not cover what you were referring to, open an issue with
*specific* suggestion for addition.
Terry Jan Reedy
More information about the Python-list