Printing out packing result from struct.pack

Question

struct.pack returns packed result from input value.

In [19]: pack("i",4)
Out[19]: '\x04\x00\x00\x00'

I'm trying to printout the packed result as follows:

val = pack("i", 4)
print "%d" % int(val[0])

However, I got ValueError:

ValueError: invalid literal for int() with base 10: '\x04'

How can I print the packed value?

Answer 1

The issue was for hexadecimal value conversion, I had to use ord() method. int() method is only for a number in a string with base 10.

In [33]: int('4')
Out[33]: 4

In [34]: ord('\x34')
Out[34]: 52

In [35]: ord('4')
Out[35]: 52

In [36]: ord('\x10')
Out[36]: 16

So, this code works.

val = pack("i", 4)
print "%d" % ord(val[0]) # -> 4

or

print "%s" % hex(ord(val[0])) # -> 0x4