Python split string in bytes

How to split a byte string into separate bytes in python

When handling these frames, however, you probably also want to know about memoryview() objects; these let you interpret the bytes as C datatypes without any extra work on your part, simply by casting a ‘view’ on the underlying bytes:

>>> mv = memoryview(value).cast('H') >>> mv[0], mv[1], mv[2] 256, 512, 768 

The mv object is now a memory view interpreting every 2 bytes as an unsigned short; so it now has length 3 and each index is an integer value, based on the underlying bytes.

You are actually asking about serialization/deserialization. Use struct.pack and struct.unpack (https://docs.python.org/3/library/struct.html). This gives you nice primitives to do both unpacking and things like endian swapping. For example:

import struct struct.unpack("l",b"\x00\x01\x02\x03") # unpacks 4 byte big endian signed int 

Note that your example splits 2 byte words, not bytes.

Since this question is also coming up in searches about splitting binary strings:

value = b'\x00\x01\x00\x02\x00\x03' split = [value[i] for i in range (0, len(value))] # now you can modify, for example: split[1] = 5 # put it back together joined = bytes(split) 

Here is a way that you can split the bytes into a list:

data = b'\x00\x00\x00\x00\x00\x00' info = [data[i:i+2] for i in range(0, len(data), 2)] print info 

kyle k 4714

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How to split a byte string into separate bytes in python

179H S 186H S 193H S 203H S 217H S 214H S 219H S 226H S 234H S 215H S 229H S 220H S 212H S 211H S Split strings with strings, bytes with bytes.

How to split a byte string into separate bytes in python

Ok so I’ve been using python to try create a waveform image and I’m getting the raw data from the .wav file using song = wave.open() and song.readframes(1) , which returns :

What I want to know is how I split this into three separate bytes, e.g. b’\x00\x00′ , b’\x00\x00′ , b’\x00\x00′ because each frame is 3 bytes wide so I need the value of each individual byte to be able to make a wave form. I believe that’s how I need to do it anyway.

You can use slicing on byte objects:

>>> value = b'\x00\x01\x00\x02\x00\x03' >>> value[:2] b'\x00\x01' >>> value[2:4] b'\x00\x02' >>> value[-2:] b'\x00\x03' 

When handling these frames, however, you probably also want to know about memoryview() objects; these let you interpret the bytes as C datatypes without any extra work on your part, simply by casting a ‘view’ on the underlying bytes:

>>> mv = memoryview(value).cast('H') >>> mv[0], mv[1], mv[2] 256, 512, 768 

The mv object is now a memory view interpreting every 2 bytes as an unsigned short ; so it now has length 3 and each index is an integer value, based on the underlying bytes.

Here is a way that you can split the bytes into a list:

data = b'\x00\x00\x00\x00\x00\x00' info = [data[i:i+2] for i in range(0, ****(data), 2)] print info 

You are actually asking about serialization/deserialization. Use struct.pack and struct.unpack (https://docs.python.org/3/library/struct.html). This gives you nice primitives to do both unpacking and things like endian swapping. For example:

import struct struct.unpack("l",b"\x00\x01\x02\x03") # unpacks 4 byte big endian signed int 

Note that your example splits 2 byte words, not bytes.

Since this question is also coming up in searches about splitting binary strings:

value = b'\x00\x01\x00\x02\x00\x03' split = [value[i] for i in range (0, ****(value))] # now you can modify, for example: split[1] = 5 # put it back together joined = bytes(split) 

How to split bytes into a list of integers in Python-3?, [int(x) for x in input.decode(). · So you are just splitting on whitespace? – Martijn Pieters · Alternatively list(map(int, input.decode(). · 1. @

How to split a byte string into separate bytes in python

How to split a byte string into separate bytes in python — Array [ Glasses to protect eyes while Duration: 1:06

Split byte string into lines

How can I split a byte string into a list of lines?

rest = "some\nlines" for line in rest.split("\n"): print line 

The code above is simplified for the sake of brevity, but now after some regex processing, I have a byte array in rest and I need to iterate the lines.

There is no reason to convert to string. Just give split bytes parameters. Split strings with strings, bytes with bytes.

>>> a = b'asdf\nasdf' >>> a.split(b'\n') [b'asdf', b'asdf'] 

Decode the bytes into unicode (str) and then use str.split :

Python 3.2.3 (default, Oct 19 2012, 19:53:16) [GCC 4.7.2] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> a = b'asdf\nasdf' >>> a.split('\n') Traceback (most recent call last): File "", line 1, in TypeError: Type str doesn't support the buffer API >>> a = a.decode() >>> a.split('\n') ['asdf', 'asdf'] >>> 

You can also split by b’\n’ , but I guess you have to work with strings not bytes anyway. So convert all your input data to str as soon as possible and work only with unicode in your code and convert it to bytes when needed for output as late as possible.

rest = b»some\nlines»
rest=rest.decode(«utf-8»)

then you can do rest.split(«\n»)

How to Convert Int to Bytes in Python?, An int object can be used to represent the same value in the format of the byte. The integer represents a byte, is stored as an array with

Splitting byte string into columns

I have extracted some historical weather data and it’s output in a large byte string format like:

ASN00040223194410TAVG 192H S 206H S 188H S 196H S 186H S 194H S 198H S 204H S 205H S 212H S 224H S 223H S 216H S 221H S 228H S 216H S 207H S 179H S 186H S 193H S 203H S 217H S 214H S 219H S 226H S 234H S 215H S 229H S 220H S 212H S 211H S

This string has a set format that I pulled apart using df.str.extract and then using a regex to match the pattern. For instance, the first 11 chars are the station ID, next 4 are the year, next 2 are the month, etc.

First question — is there an easier way to set up this parsing of the byte string? For example I’d like to be able to write a table like this:

and i want to turn that into a regular expression that gives me dataframe with each of the Names as columns like:

Ok, so part 2 of the question is after i have this dataframe i have columns with Value1, Flag1, Value2, Flag2 etc. These represent the values and flags for each day of the month. How can I turn each row with the year and month into separate rows with a datetime and their respective values:

help would be appreciated!

For your first question, you could write a custom function that converts the string passed to a pandas.DataFrame :

def construct(string, config): d = dict() for name, chars in zip(config["Name"], config["Chars"]): start, end = [int(i) for i in chars.split("-")] d[name] = string[start-1:end].****() return pd.DataFrame(d, index=[0]) 

string = "ASN00040223194410TAVG 192H S 206H S 188H S 196H S 186H S 194H S 198H S 204H S 205H S 212H S 224H S 223H S 216H S 221H S 228H S 216H S 207H S 179H S 186H S 193H S 203H S 217H S 214H S 219H S 226H S 234H S 215H S 229H S 220H S 212H S 211H S" >>> config Name Chars 0 StationID 1-11 1 Year 12-15 2 Month 16-17 3 Element 18-21 4 Value1 22-26 5 Value2 27-31 >>> construct(string, config) StationID Year Month Element Value1 Value2 0 ASN00040223 1944 10 TAVG 192H S 20 

Splitting bytes into «16 bit words», I have the following task: Write a function split(data: bytes) -> List[int] that splits the input from data into 16 bit long segments,

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