[Bug] i.spectral: Textual output format seems incoherent

[echoix]

Describe the bug

The code in question is:

grass/scripts/i.spectral/i.spectral.py

Lines 91 to 98 in 1953975

	def write2textf(what, output):
	outf = open(output, "w")
	i = 0
	for row in enumerate(what):
	i = i + 1
	outf.write("%d, %s\n" % (i, row))
	outf.close()

Here it's not related to this issue specifically, but I don't undestand why enumerate is used here, but the count it provides isn't used here. (Enumerate is to go through the iterable, but also bundle the index in a tuple, by default the start argument is at 0). And the loop also keeps track of an i variable. Are we sure that the output that is written to the file is what is expected? It writes i as a %d (a number), but then row as a %s (a string). Without running it, it should then be the string representation of the row, that is in fact here a tuple of the count and the item of what. Is it expected? Where is it used?

Originally posted by @echoix in #4134 (comment)

To me it seems like a glitch, when the script was ported from shell to Python.

There are no examples or tests that can be used as a reference for how the textfile output is supposed to look like. With the current code it will look something like this:

1, (0, [1, 1, 255, 45, 65])
2, (1, [2, 2, 255, 233, 165])
3, (2, [3, 3, 125, 133, 155])
4, (3, [4, 4, 167, 34, 67])

That does not seem natural to me as I would expect rather CSV like text output...

I would likely go for something like:

Path(output).write_text("\n".join([f"{i},{','.join(map(str, row))}"for i, row in enumerate(what, 1)]) + "\n")

Unless there is a reason for the current output format...

Originally posted by @ninsbl in #4134 (comment)

I'm for using i, row with enumerate and outputting just that. That looks like the intention in the original code. I'm not sure how this compares to the one-liner.

Originally posted by @wenzeslaus in #4134 (comment)

Expected behavior

A usable output format

Additional context

See the linked thread to follow.