Is there a built-in function to replace multiple bytes?

Is there a built-in function to replace multiple bytes? - Printable Version

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Is there a built-in function to replace multiple bytes? - Raptor88 - Feb-24-2017

I'm learning Python 3.6.

I figured out how to use the find() function to find a multiple hex byte string in a byte variable as follows:

with open("test 18.vf", "rb") as binaryFile:
    byteData = bytearray(binaryFile.read()) 

mx = 0
while mx != -1:
    mx = byteData.find(b'\x2A\x07\x3B\x1C\x14', mx)
    if mx != -1:
        Do something

Is there a built-in function to change consecutive bytes in "byteData" that looks similar to the find function above?
If not, any suggestions on the easiest way to replace 7 consecutive bytes? I won't be inserting any bytes. Just replacing 7 consecutive bytes elsewhere in "byteData".

Thanks.

RE: Is there a built-in function to replace multiple bytes? - Larz60+ - Feb-24-2017

Untested, but this should work:

replace:

   mx = byteData.find(b'\x2A\x07\x3B\x1C\x14', mx)

with:

   bytedata=butedata.replace(b'\x2A\x07\x3B\x1C\x14', b'New value here')

RE: Is there a built-in function to replace multiple bytes? - Raptor88 - Feb-24-2017

(Feb-24-2017, 08:01 PM)Larz60+ Wrote: Untested, but this should work:

replace:
   mx = byteData.find(b'\x2A\x07\x3B\x1C\x14', mx)
with:
   bytedata=butedata.replace(b'\x2A\x07\x3B\x1C\x14', b'New value here')

Thanks Larz60+. I won't know the bytes to be replaced as they could vary depending on the user's setup. I neglected to say that I will be replacing the 7 bytes based on the index value of "mx".

For example:
1. Search for the 5 byte string.
2. If found, mx = index of first found byte.
3. Add a value to mx to skip bytes. Like mx += 52.
4. Replace 7 bytes starting from the current index value of mx.
5. Repeat steps 1-4 until the end of "byteData" signified by mx == -1.

Sorry for not being more through in my initial post.
Thanks.

RE: Is there a built-in function to replace multiple bytes? - zivoni - Feb-24-2017

If you want to replace 7 bytes from given index mx, you can do

byteData[mx : mx+7] = 1, 2, 3, 4, 5, 6, 7

bytearray is mutable, so it will work. And if you want these bytes replaced with different number of bytes, you can use .insert() method or del byteData[index1: index2].

RE: Is there a built-in function to replace multiple bytes? - Raptor88 - Feb-25-2017

(Feb-24-2017, 11:53 PM)zivoni Wrote: If you want to replace 7 bytes from given index mx, you can do
byteData[mx : mx+7] = 1, 2, 3, 4, 5, 6, 7
bytearray is mutable, so it will work. And if you want these bytes replaced with different number of bytes, you can use .insert() method or del byteData[index1: index2].

Hi zivoni,

So simple, so easy, so clean.

Works perfectly, So thanks!
Raptor88