File Read issue by using module binascii

[Peter Otten]

Jimmie He wrote:

>> What shell are you using? The one provided by Idle?
> 
> Yes. I use IDLE,the python version is 3.3.1.What else could I use??

The shell provided by the operating system is usually much faster. When I 
modify your code to

import binascii

def read_bmp():
    f = open('example.bmp','rb')
    rawdata = f.read()                       #f.read(1000) is ok
    hexstr = binascii.b2a_hex(rawdata)       #Get an HEX number
    bsstr = bin (int(hexstr,16))[2:]
    f.close()
    print('bin: ',bsstr,type(bsstr))
    return

if __name__ == "__main__":
    read_bmp()

and generate a dummy example.bmp with 2**20 (about 1 million) bytes it takes 
about 2 seconds to terminate -- on hardware that is quite old. If I redirect 
the output it is even faster:

$ time python3 bmp_to_bin.py > /dev/null

real    0m0.766s
user    0m0.300s
sys     0m0.180s

I am a Linux user, but expect similar numbers on Windows (in the DOS box or 
one of its successors).

I have considered filing a bug* to ask for a tweak in idle that improves its 
responsiveness, but first wanted you to confirm that this was indeed the 
problem.

(*) on http://bugs.python.org, if you want to do it yourself