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Python __call__ special method practical example
I know that __call__ method in a class is triggered when the instance of a class is called. However, I have no idea when I can use this special method, because one can simply create a new method and perform the same operation done in __call__ method and instead of calling the instance, you can c...
Cron job every three days
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The answer is not correct because neither suggestion actually runs the job every 3 days. 0 0 */3 * * means run on the 1st, 4th, 7th, etc. (*/3 means 1-31/3 means 1,4,7...31) so the gap will be smaller at the end of the month. (It'll run 2 days in a row if the previous month had 3...
How to hash some string with sha256 in Java?
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SHA-256 isn't an "encoding" - it's a one-way hash.
You'd basically convert the string into bytes (e.g. using text.getBytes(StandardCharsets.UTF_8)) and then hash the bytes. Note that the result of the hash would also be arbitrary binary data, and if you want to represent that in a strin...
Determine if variable is defined in Python [duplicate]
...ime? This is not always obvious because (1) the variable could be conditionally set, and (2) the variable could be conditionally deleted. I'm looking for something like defined() in Perl or isset() in PHP or defined? in Ruby.
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The difference between sys.stdout.write and print?
...ble, but by default with a space between args and newline at the end) and calls the write function of a given object. By default this object is sys.stdout, but you can pass a file using the "chevron" form. For example:
print >> open('file.txt', 'w'), 'Hello', 'World', 2+3
See: https://docs....
How to get a string after a specific substring?
...("world",1)[1]
split takes the word(or character) to split on and optionally a limit to the number of splits.
In this example split on "world" and limit it to only one split.
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When to use Comparable and Comparator
... | Comparable | Comparator
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Is used to allow Collections.sort to work | yes | yes
Can compare multiple fields | yes ...
Using pg_dump to only get insert statements from one table within database
I'm looking for a way to get all rows as INSERT statements from one specific table within a database using pg_dump in PostgreSQL.
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Add swipe to delete UITableViewCell
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@lase You might want to take a peek at an app called Dash. It enables you to search documentation and it's a lot snappier than browsing the web. It's also stored locally on your computer, so you don't need web access to look stuff up. You can also load up documentation fo...
Installing SciPy with pip
It is possible to install NumPy with pip using pip install numpy .
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