delete_curve issue

[hflesche]

If you loop through curves in a las-file to delete some of them, the result is not correct unless you start from the last curve and move forwards. Let's say we have a las object with curves DEPTH, BS, CALI, RHOB, DT and DTS. The following code will skip CALI when BS curve is deleted:

keep_curves = ['DEPTH', 'DT', 'DTS']
for curve in las_file.curves:
    if curve.mnemonic not in keep_curves:
        las_file.delete_curve(curve.mnemonic)

whereas if the list of curves is reversed, the correct ones are deleted:

use_curves = ['DEPT', 'DT', 'DTS']
for curve in reversed(las_file.curves):
    if curve.mnemonic not in keep_curves:
        las_file.delete_curve(curve.mnemonic)

[kinverarity1]

Thanks @hflesche, I will have a look at this tomorrow.

[kinverarity1]

I have a feeling this is always likely to fail, e.g. https://stackoverflow.com/a/2897058/596328

Out of curiosity, does adding a slice to obtain a copy (see below) work for you?

keep_curves = ['DEPTH', 'DT', 'DTS']
for curve in las_file.curves[:]:
    if curve.mnemonic not in keep_curves:
        las_file.delete_curve(curve.mnemonic)

[hflesche]

Yes, that works. Another option that also works is this:

for curve_name in las_file.keys():
    if curve_name not in keep_curves:
        las_file.delete_curve(curve_name)

According to the link that you sent, this may not be an issue for delete_curve, it is more of a Python issue. A warning could perhaps be added to the docs, but it is not really a bug.

[kinverarity1]

Great idea, I'll add something to the docs!

…

________________________________ From: Harald Flesche <notifications@github.com> Sent: Friday, April 17, 2020 1:03:02 AM To: kinverarity1/lasio <lasio@noreply.github.com> Cc: Kent Inverarity <kinverarity@hotmail.com>; Comment <comment@noreply.github.com> Subject: Re: [kinverarity1/lasio] delete_curve issue (#315) Yes, that works. Another option that also works is this: for curve_name in las_file.keys(): if curve_name not in keep_curves: las_file.delete_curve(curve_name) According to the link that you sent, this may not be an issue for delete_curve, it is more of a Python issue. A warning could perhaps be added to the docs, but it is not really a bug. — You are receiving this because you commented. Reply to this email directly, view it on GitHub<https://eur05.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fkinverarity1%2Flasio%2Fissues%2F315%23issuecomment-614726293&data=02%7C01%7C%7C8b14ad9672d34677530508d7e21b7414%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637226479846110417&sdata=0oLHnnql8ONFeuJWqqPbGBz9I3uBc7AfKB1eVdv8nRw%3D&reserved=0>, or unsubscribe<https://eur05.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fnotifications%2Funsubscribe-auth%2FABCQ626OV6TN6EAUPDRCUSLRM4QK5ANCNFSM4MJF22SA&data=02%7C01%7C%7C8b14ad9672d34677530508d7e21b7414%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637226479846120412&sdata=jQJ3XP%2BFMdxnSrEerWaP1lZshXO5p6u5KK9jmMfDgoA%3D&reserved=0>.