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Efficient way to apply multiple filters to pandas DataFrame or Series
I have a scenario where a user wants to apply several filters to a Pandas DataFrame or Series object. Essentially, I want to efficiently chain a bunch of filtering (comparison operations) together that are specified at run-time by the user.
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Equation (expression) parser with precedence?
...'ve developed an equation parser using a simple stack algorithm that will handle binary (+, -, |, &, *, /, etc) operators, unary (!) operators, and parenthesis.
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How to make good reproducible pandas examples
Having spent a decent amount of time watching both the r and pandas tags on SO, the impression that I get is that pandas questions are less likely to contain reproducible data. This is something that the R community has been pretty good about encouraging, and thanks to guides like this , newc...
Conventions for exceptions or error codes
...error codes.
The default behaviour of an exception is to unwind the stack and stop the program, if I'm writing a script an and I go for a key that's not in a dictionary it's probably an error, and I want the program to halt and let me know all about that.
If, however, I'm writing a piece of code ...
How to create a self-signed certificate with OpenSSL
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You can do that in one command:
openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem -days 365
You can also add -nodes (short for no DES) if you don't want to protect your private key with a passphrase. Otherwise it will prompt you for "...
JavaScript variables declare outside or inside loop?
...rmance, in JavaScript or ActionScript.
var is a directive for the parser, and not a command executed at run-time. If a particular identifier has been declared var once or more anywhere in a function body(*), then all use of that identifier in the block will be referring to the local variable. It ma...
What is this operator in MySQL?
I'm working on code written by a previous developer and in a query it says,
9 Answers
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Secure hash and salt for PHP passwords
...nswer was written in 2008.
Since then, PHP has given us password_hash and password_verify and, since their introduction, they are the recommended password hashing & checking method.
The theory of the answer is still a good read though.
TL;DR
Don'ts
Don't limit what characters user...
Is it wrong to use Deprecated methods or classes in Java?
...t in the API for backward compatibility for an unspecified period of time, and may in future releases be removed. That is, no, it's not wrong, but there is a better way of doing it, which is more robust against API changes.
2. What if I don't change any method and run my application with warning...
Checking if a key exists in a JavaScript object?
...r, if you want to particularly test for properties of the object instance (and not inherited properties), use hasOwnProperty:
obj.hasOwnProperty("key") // true
For performance comparison between the methods that are in, hasOwnProperty and key is undefined, see this benchmark
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