transform strings list in a int lists or other type???

Dennis Lee Bieber wlfraed at
Wed Sep 25 23:19:37 EDT 2002

jubafre at fed this fish to the penguins on Wednesday 25 
September 2002 04:29 pm:

        Haven't you asked a version of this /each/ day for the last few days?

>                   Can i tranform a list of strings in a list of int,
>                   or other type in python???
> and also write in a file? I think the open(path,'wb') in __builtin__
> dont´t write in a file other types, just strings, rigth???

        ALL I/O in Python is effectively a stream of bytes. The "b" option on 
the open ONLY controls the interpretation of line-endings. IE, on 
Windows reading a file with "b" means you see both the <cr> and the 
<lf> character; without the "b" (normal mode) the <cr><lf> is converted 
to just a "newline" (<lf>) for internal use.

        To write a "binary" file requires you to either manipulate /each/ byte 
of your data, OR to use the struct module to pack your data into a 
string (full of unprintable characters) which can be written.

import struct
ots = struct.pack(">2L2H12s30pB", 0x10346f89, 563993, 0x0d0a, 32767,
        "Some Text", "More text with a count byte", ord("\r")

print ots

Lots of unprintables in that... Cut&Pasted from the terminal window:
4o›       ore text with a count byte

print repr(ots)

'\x104o\x89\x00\x08\x9b\x19\r\n\x7f\xffSome Text\x00\x00\x00\x1bMore 
text with a count byte\x00\x00\r'

        I used the ">" in the pack format string to ensure that the byte 
sequence for output is "big-end first" so the output representation is 
the same as the input numbers -- default on my machine is "little-end 

0x10346f89      to the output... You have to take into account that 
printable characters show up as single byte characters rather than an 
encoded \xnn set.

0x10   34   6f   89
\x10    4    o \x89

 > ============================================================== <
 >   wlfraed at  | Wulfraed  Dennis Lee Bieber  KD6MOG <
 >      wulfraed at     |       Bestiaria Support Staff       <
 > ============================================================== <
 >        Bestiaria Home Page:         <
 >            Home Page:             <

More information about the Python-list mailing list