Re: issue with struct.unpack
This is what I have to reproduce the challenge I am having below:
import csv
import struct
data = []
for Node in csv.reader(file('s_data.xls')):
data.append(list((file('s_data.xls'
data = struct.unpack('!B4HH', data)
print s_data.csv: , data
I tries so many format for the struct.unpack but I got this errors:
Traceback (most recent call last):
data = struct.unpack('!B4HH', data)
struct.error: unpack requires a string argument of length 11
On Saturday, 25 August 2012 19:34:39 UTC+1, 9bizy wrote:
I am trying to unpack values from sensor data I am retrieving through a
serial cable, but I get errors while using struct.unpack, how can I use
struct.unpack to unload the data in a readable format?
I checked the python documentation for struct and I can seen to find any
argument for this.
I have data = struct.unpack('char',data) but I still get errors
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Re: issue with struct.unpack
On Saturday, 25 August 2012 20:16:54 UTC+1, MRAB wrote:
On 25/08/2012 19:34, 9bizy wrote:
I am trying to unpack values from sensor data I am retrieving through
a serial cable, but I get errors while using struct.unpack, how can I
use struct.unpack to unload the data in a readable format?
I checked the python documentation for struct and I can seen to find
any argument for this.
I have data = struct.unpack('char',data) but I still get errors
The format strings are described here for Python 3:
http://docs.python.org/3.2/library/struct.html
and here for Python 2:
http://docs.python.org/2.7/library/struct.html
I used this documents but they do not explain or provide an example on how to
use struct.unpack for sensor data from an external source or even data from a
excel sheet.
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Re: issue with struct.unpack
On Tuesday, 28 August 2012 23:49:54 UTC+1, MRAB wrote:
On 28/08/2012 23:34, 9bizy wrote:
This is what I have to reproduce the challenge I am having below:
import csv
import struct
data = []
for Node in csv.reader(file('s_data.xls')):
That tries to read the file as CSV, but, judging from the extension,
it's in Excel's format. You don't even use what is read, i.e. Node.
data.append(list((file('s_data.xls'
That opens the file again and 'list' causes it to read the file as
though it were a series of lines in a text file, which, as I've said,
it looks like it isn't. The list of 'lines' is appended to the list
'data', so that's a list of lists.
data = struct.unpack('!B4HH', data)
print s_data.csv: , data
I tries so many format for the struct.unpack but I got this errors:
Traceback (most recent call last):
data = struct.unpack('!B4HH', data)
struct.error: unpack requires a string argument of length 11
[snip]
It's complaining because it's expecting a string argument but you're
giving it a list instead.
How do I then convert data to a string argument in this case?
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Re: issue with struct.unpack
On Wednesday, 29 August 2012 00:36:40 UTC+1, MRAB wrote:
On 29/08/2012 00:01, 9bizy wrote: On Tuesday, 28 August 2012 23:49:54
UTC+1, MRAB wrote:
On 28/08/2012 23:34, 9bizy wrote:
This is what I have to reproduce the challenge I am having below:
import csv
import struct
data = []
for Node in csv.reader(file('s_data.xls')):
That tries to read the file as CSV, but, judging from the extension,
it's in Excel's format. You don't even use what is read, i.e. Node.
data.append(list((file('s_data.xls'
That opens the file again and 'list' causes it to read the file as
though it were a series of lines in a text file, which, as I've said,
it looks like it isn't. The list of 'lines' is appended to the list
'data', so that's a list of lists.
data = struct.unpack('!B4HH', data)
print s_data.csv: , data
I tries so many format for the struct.unpack but I got this errors:
Traceback (most recent call last):
data = struct.unpack('!B4HH', data)
struct.error: unpack requires a string argument of length 11
[snip]
It's complaining because it's expecting a string argument but you're
giving it a list instead.
How do I then convert data to a string argument in this case?
The question is: what are you trying to do?
If you're trying to read an Excel file, then you should be trying the
'xlrd' module. You can find it here: http://www.python-excel.org/
If your trying to 'decode' a binary file, then you should open it in
binary mode (with rb), read (some of) it as a byte string and then
pass it to struct.unpack.
Thank you MRAB this was helpful.
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issue with struct.unpack
I am trying to unpack values from sensor data I am retrieving through a serial
cable, but I get errors while using struct.unpack, how can I use struct.unpack
to unload the data in a readable format?
I checked the python documentation for struct and I can seen to find any
argument for this.
I have data = struct.unpack('char',data) but I still get errors
--
http://mail.python.org/mailman/listinfo/python-list
