Tutorials and instructions usually recommend dd over cp for copying disc images to devices (like USB sticks). It seems that this is mostly superstition.
The main benefit is that dd lets you specify the block size used for copying, but cp automatically selects the block size at least as well as I would.
The other benefit of dd is a progress display. Piping the output of the pv command to the destination disc may be a better option.
A really nice explanation of how to use SystemD timers to replace cron.
I've needed to do this countless times in particle physics data analysis and other areas.
What I've done before:
data = {'a' : ['alpha', "beta"], 'b' : ["alpha"]}
result = {}
for key in data:
for value in data[key]:
try:
result[value].append(key)
except KeyError:
result[value] = [key]and the simpler solutions suggested in the link:
data = {'a' : ['alpha', "beta"], 'b' : ["alpha"]}
result = {}
for key in data:
for value in data[key]:
result.setdefault(value,[]).append(key)or
from collections import defaultdict
data = {'a' : ['alpha', "beta"], 'b' : ["alpha"]}
result = defaultdict(list)
for key in data:
for value in data[key]:
result[value].append(key)dict.setdefault and collections.defaultdict are new to me and useful!
A really nice guide to the best, most secure ways to do website authentication. Lots of nice links