Peter, I see that clue "[[".
The thread history pretty much sums up what is going on up to this point. I'll cover it once more: I'm using Adafruit FT232H Breakout board and Adafruit's library. https://github.com/adafruit/Adafruit_Python_GPIO Per Adafruit's example code, I create an SPI interface: https://learn.adafruit.com/adafruit-ft232h-breakout?view=all I can access this interface with the spi.transfer() spi.write() and spi.read() functions. The transfer() function (see link above) accepts and returns bytearray objects data. My application requires me to send a large payload down the SPI port to my circuit, and read back the same in full duplex. Due to a limitation of the part, I can't send my whole bytearray at one time. It crashes out. So, my solution was to send as large of a chunk of data at one time as I can inside a loop until I get to the end of the data to be sent. Meanwhile, the transfer() function is returning 'chunks' of bytearrays. Earlier discussions here indicated that the best way was to : results = [] for i in range (0, slice_size): results.append(transfer(data_out)) Then, concatenate the results into a long bytearray so I can use it elsewhere in my code. all_together = bytearray().join(results) I _thought_ that this was going to create a concatenated list of all the returned results: all_together = [results[0] + results[1] + results [2] + results[3]] -- for example but, as you point out, I got: all_together = [[results[0]], [results[1]], [results[2]]. [results[3]] -- I'm sure that the brackets and braces are not syntactically correct, but I think you get the idea. So I see why my .join() isn't working. I'm not sure how to fix it though. Related to this, but I'm not yet at that point until I get this resolved, I need to walk through the all_together data and find where the data changes from one value to another.. My background is in C and other 'historical' languages, so I'm trying to get a hold of the way Python handles arrays, which is different that the way I've thought for 20+ years.. :) I hope this helps. I'm beginning to wonder if Python was the right choice for this project.. but it's too late for me to switch now. Thanks to everyone for your comments and patience. On Mon, Sep 10, 2018 at 1:42 PM, Peter Otten <__pete...@web.de> wrote: > Chip Wachob wrote: > >> Cameron, >> >> Thank you again for the insight. >> >> Yes, data_out is an equivalently-sized 'chunk' of a larger array. >> >> I'm 'getting' this now.. >> >> So, without all the fluff associated with wiggling lines, my function >> now looks like this: >> >> def RSI_size_the_loop(): >> results = [] >> all_together = [] # not certain if I need this, put it in in an >> attempt to fix the incompatibility if it existed >> >> for x in range (0, MAX_LOOP_COUNT, slice_size): >> results.append(my_transfer(disp, data_out, slice_size) >> >> print " results ", x, " = ", results # show how results grows >> on each iteration >> >> all_together = bytearray().join(results) >> >> print " all together ", all_together >> >> >> I can observe results increasing in size and the last time through the >> loop: >> >> results 48 = >> > [[bytearray(b'\xff\xff\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')], > > Note that there are two '[' at the start of the list. This means that the > first list item is another list. In fact you seem to have a list of single > item lists like > > [["foo"], ["bar"], ...] > > when you need > > ["foo", "bar", ...] > > Of course join will fail with that: > >>>> "".join(["foo", "bar"]) > 'foobar' >>>> "".join([["foo"], ["bar"]]) > Traceback (most recent call last): > File "<stdin>", line 1, in <module> > TypeError: sequence item 0: expected string, list found > > I think the error message is pretty clear ;) > > Have a look into your my_transfer() function to find out why it returns a > list (or show us the code). > > _______________________________________________ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > https://mail.python.org/mailman/listinfo/tutor _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
