let fetchRequest = NSFetchRequest(entityName: "Foo")
var thePredicate: NSPredicate?
thePredicate = NSPredicate(format: "message == 'example'")
The entity Foo has a message string attribute
The following example shows how you can use the pushd command and the popd command in a batch program to change the current directory from the one in which the batch program was run and then change it back:
@echo off
rem This batch file deletes all .txt files in a specified directory
pushd %1
...
If a static constructor throws an exception, it is never retried. The type is unusable for the lifetime of the AppDomain. Any further usages of the type will raise a TypeInitializationException wrapped around the original exception.
public class Animal
{
static Animal()
{
Consol...
This is a huge topic, but it is also the most important "performance" issue.
The main lesson for a novice is to learn of "composite" indexes. Here's a quick example:
INDEX(last_name, first_name)
is excellent for these:
WHERE last_name = '...'
WHERE first_name = '...' AND ...
2.12.2
You can use the minElement() and maxElement() methods to find the minimum or maximum element in a given sequence. For example, with an array of numbers:
let numbers = [2, 6, 1, 25, 13, 7, 9]
let minimumNumber = numbers.minElement() // Optional(1)
let maximumNumber = numbers.maxElement()...
As with docopt, with [docopt_dispatch] you craft your --help in the __doc__ variable of your entry-point module. There, you call dispatch with the doc string as argument, so it can run the parser over it.
That being done, instead of handling manually the arguments (which usually ends up in a high c...
The following example shows how to use a QTimer to call a slot every 1 second.
In the example, we use a QProgressBar to update its value and check the timer is working properly.
main.cpp
#include <QApplication>
#include "timer.h"
int main(int argc, char *argv[])
{
QApp...
For immutable elements (e.g. None, string literals etc.):
my_list = [None] * 10
my_list = ['test'] * 10
For mutable elements, the same construct will result in all elements of the list referring to the same object, for example, for a set:
>>> my_list=[{1}] * 10
>>> print(my_...
Unzipping a zip archive is done with unzip function from the utils package (which is included in base R).
unzip(zipfile = "bar.zip", exdir = "./foo")
This will extract all files in "bar.zip" to the "foo" directory, which will be created if necessary. Tilde...
Extracting files from a tar archive is done with untar function from the utils package (which is included in base R).
untar(tarfile = "bar.tar", exdir = "./foo")
This will extract all files in "bar.tar" to the "foo" directory, which will be created if nece...
Knitr is an R package that allows us to intermingle R code with LaTeX code. One way to achieve this is external code chunks. External code chunks allow us to develop/test R Scripts in an R development environment and then include the results in a report. It is a powerful organizational technique....
The SilverStripe Grid Field Extensions Module has some very nice features to enhance the basic GridField...
GridFieldAddExistingSearchButton - a more advanced search form for adding items
GridFieldAddNewInlineButton - builds on GridFieldEditableColumns to allow inline creation of records.
GridF...
First thing to do is enable the mod rewrite on wamp go to Apache modules and scroll down the list
If not showing tick enable it and then restart all servers.
Linux users can also use below terminal command to enable rewrite module
sudo a2enmod rewrite
Then restart apache using:
sudo service...
Scope guards allow executing statements at certain conditions if the current block is left.
import core.stdc.stdlib;
void main() {
int* p = cast(int*)malloc(int.sizeof);
scope(exit) free(p);
}
Here we have a simple class to be tested that returns a Promise based on the results of an external ResponseProcessor that takes time to execute.
For simplicty we'll assume that the processResponse method won't ever fail.
import {processResponse} from '../utils/response_processor';
const ping =...
A simple cursor syntax, operating on a few example test rows:
/* Prepare test data */
DECLARE @test_table TABLE
(
Id INT,
Val VARCHAR(100)
);
INSERT INTO @test_table(Id, Val)
VALUES
(1, 'Foo'),
(2, 'Bar'),
(3, 'Baz');
/* Test data prepared */
/* Iterator variabl...
For multiple quotechars use regex in place of sep:
df = pd.read_csv(log_file,
sep=r'\s(?=(?:[^"]*"[^"]*")*[^"]*$)(?![^\[]*\])',
engine='python',
usecols=[0, 3, 4, 5, 6, 7, 8],
names=['ip', 'time', 'request', 'statu...
This function executes an AJAX request using the HEAD method allowing us to check whether a file exists in the directory given as an argument. It also enables us to launch a callback for each case (success, failure).
function fileExists(dir, successCallback, errorCallback) {
var xhttp = new XM...
CPython allows access to the code object for a function object.
The __code__object contains the raw bytecode (co_code) of the function as well as other information such as constants and variable names.
def fib(n):
if n <= 2: return 1
return fib(n-1) + fib(n-2)
dir(fib.__code__)
de...
