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How to “test” NoneType in python?
...ariable has None in it or not.
Quoting from is docs,
The operators is and is not test for object identity: x is y is true if and only if x and y are the same object. x is not y yields the inverse truth value.
Since there can be only one instance of None, is would be the preferred way to check...
Maximum number of characters using keystrokes A, Ctrl+A, Ctrl+C and Ctrl+V
.... Then we iterate through for i up to n, doing two things: pressing A once and pressing select all + copy followed by paste j times (actually j-i-1 below; note the trick here: the contents are still in the clipboard, so we can paste it multiple times without copying each time). We only have to consi...
Why does Google prepend while(1); to their JSON responses?
...de the URL via a <script> tag. The URL is visited with your cookies, and by overriding the global array constructor or accessor methods they can have a method called whenever an object (array or hash) attribute is set, allowing them to read the JSON content.
The while(1); or &&&BL...
What is the recommended way to delete a large number of items from DynamoDB?
...o do is call LogTable.DeleteItem(user_id) -
Without supplying the range, and have it delete everything for me.
An understandable request indeed; I can imagine advanced operations like these might get added over time by the AWS team (they have a history of starting with a limited feature set firs...
How to round up to the nearest 10 (or 100 or X)?
...en James answer seems most appropriate. My version lets you take any value and automatically round it to a reasonably "nice" value. Some other good choices of the "nice" vector above are: 1:10, c(1,5,10), seq(1, 10, 0.1)
If you have a range of values in your plot, for example [3996.225, 40001.893] ...
Spring DAO vs Spring ORM vs Spring JDBC
I was going through data access technologies supported by Spring, and I noticed that it mentions multiple options and I am not sure about the difference among them:
...
JavaScript OR (||) variable assignment explanation
... variable is falsy.
The boolean operators in JavaScript can return an operand, and not always a boolean result as in other languages.
The Logical OR operator (||) returns the value of its second operand, if the first one is falsy, otherwise the value of the first operand is returned.
For example:...
Difference between numpy.array shape (R, 1) and (R,)
...ning of shapes in NumPy
You write, "I know literally it's list of numbers and list of lists where all list contains only a number" but that's a bit of an unhelpful way to think about it.
The best way to think about NumPy arrays is that they consist of two parts, a data buffer which is just a block...
Check if a string matches a regex in Bash script
...=~ ^regex$ ]] && echo "matched" || echo "did not match"
where commands after && are executed if the test is successful, and commands after || are executed if the test is unsuccessful.
Note this is based on the solution by Aleks-Daniel Jakimenko in User input date format verification...
A semantics for Bash scripts?
...ripts that appear to work. However, I don't really know what's going on, and I was hoping for a more formal introduction to Bash as a programming language. For example: What is the evaluation order? what are the scoping rules? What is the typing discipline, e.g. is everything a string? What is the...