Concise way to format list/array to custom(hex) string

[Kurien Mathew]

Hello,

What will be a concise & efficient way to convert a list/array.array of
n elements into a hex string? For e.g. given the bytes
[116, 111, 110, 103, 107, 97]
I would like the formatted string
0x74 0x6f 0x6e 0x67 0x6b 0x61

Is there an approach better than below:
hex = ''
for b in bytes:
hex += ('0x%x '%b)


Thanks
Kurien

Test program:
import array
import sys

bytes = array.array('B')
bytes.fromstring("tongka")
print bytes
hex = ''
for b in bytes:
hex += ('0x%x '%b)
print hex

 

[John Machin]

Hello,

What will be a concise & efficient way to convert a list/array.array of
n elements into a hex string? For e.g. given the bytes
[116, 111, 110, 103, 107, 97]
I would like the formatted string
0x74 0x6f 0x6e 0x67 0x6b 0x61

Is there an approach better than below:
hex = ''
for b in bytes:
hex += ('0x%x '%b)

hex = ' '.join('0x%02x' % b for b in bytes)

 

[Zoltán Nagy]

Kurien Mathew írta:

Hello,

What will be a concise & efficient way to convert a list/array.array of
n elements into a hex string? For e.g. given the bytes
[116, 111, 110, 103, 107, 97]
I would like the formatted string
0x74 0x6f 0x6e 0x67 0x6b 0x61

Is there an approach better than below:
hex = ''
for b in bytes:
hex += ('0x%x '%b)

<snip>

You should avoid multiple string additions, as each one creates a new
string object (str objects are immutable). Try this:

bytes = [116, 111, 110, 103, 107, 97]
string = ''.join( ['0x%x '%b for b in bytes] )

 

[josh logan]

Kurien Mathew írta:

Hello,
What will be a concise & efficient way to convert a list/array.array of
n elements into a hex string? For e.g. given the bytes
[116, 111, 110, 103, 107, 97]
I would like the formatted string
0x74 0x6f 0x6e 0x67 0x6b 0x61
Is there an approach better than below:
hex = ''
for b in bytes:
    hex += ('0x%x '%b)

<snip>

You should avoid multiple string additions, as each one creates a new
string object (str objects are immutable). Try this:

bytes = [116, 111, 110, 103, 107, 97]
string = ''.join( ['0x%x '%b for b in bytes] )

That results in an extra ' ' and the end of the string.  Try
this:

string = ' '.join(['0x%02x' % b for b in bytes])

There is also a built-in hex() method in the Python Standard Library.
So, to make it cleaner:
' '.join(hex(x) for x in bytes)