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Setting an environment variable before a command in Bash is not working for the second command in a
In a given shell, normally I'd set a variable or variables and then run a command. Recently I learned about the concept of prepending a variable definition to a command:
...
Creating functions in a loop
...have a function that accesses a global variable, like this:
global_var = 'foo'
def my_function():
print(global_var)
global_var = 'bar'
my_function()
When you read this code, you would - of course - expect it to print "bar", not "foo", because the value of global_var has changed after the fu...
AWS S3 copy files and folders between two buckets
...rows the following error A client error (PermanentRedirect) occurred when calling the ListObjects operation: The bucket you are attempting to access must be addressed using the specified endpoint. Please send all future requests to this endpoint.
– Giovanni Bitliner
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Test if a variable is a list or tuple
... excludes custom sequences, iterators, and other things that you might actually need. However, sometimes you need to behave differently if someone, for instance, passes a string. My preference there would be to explicitly check for str or unicode like so:
import types
isinstance(var, types.String...
Python Remove last 3 characters of a string
...
Removing any and all whitespace:
foo = ''.join(foo.split())
Removing last three characters:
foo = foo[:-3]
Converting to capital letters:
foo = foo.upper()
All of that code in one line:
foo = ''.join(foo.split())[:-3].upper()
...
Test PHP headers with PHPUnit
...78
Error: Class 'PHPUnit_Util_Configuration' not found in - on line 378
Call Stack:
0.0013 582512 1. {main}() -:0
Try add this to your bootstrap file to fix it:
<?php
if (!defined('PHPUNIT_COMPOSER_INSTALL')) {
define('PHPUNIT_COMPOSER_INSTALL', __DIR__ . '/path/to/composer/ven...
String comparison in Python: is vs. == [duplicate]
...
For all built-in Python objects (like
strings, lists, dicts, functions,
etc.), if x is y, then x==y is also
True.
Not always. NaN is a counterexample. But usually, identity (is) implies equality (==). The converse is n...
What does the Reflect object do in JavaScript?
...ble:
ES6 spec, Reflection
MDN Reflect (including details and examples to all of its methods)
Original answer (for (historic) understanding and extra examples):
The Reflection proposal seems to have progressed to the Draft ECMAScript 6 Specification. This document currently outlines the Reflect...
How do I get a PHP class constructor to call its parent's parent's constructor?
I need to have a class constructor in PHP call its parent's parent's (grandparent?) constructor without calling the parent constructor.
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How to test if list element exists?
...
This is actually a bit trickier than you'd think. Since a list can actually (with some effort) contain NULL elements, it might not be enough to check is.null(foo$a). A more stringent test might be to check that the name is actually defin...