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How to delete or add column in SQLITE?
...upports a limited subset of ALTER TABLE. The ALTER TABLE command in SQLite allows the user to rename a table or to add a new column to an existing table. It is not possible to rename a column, remove a column, or add or remove constraints from a table.
You can:
create new table as the one you ar...
Object of custom type as dictionary key
...
You need to add 2 methods, note __hash__ and __eq__:
class MyThing:
def __init__(self,name,location,length):
self.name = name
self.location = location
self.length = length
def __hash__(self):
return hash((self.name...
Get list of a class' instance methods
...
You actually want TestClass.instance_methods, unless you're interested in what TestClass itself can do.
class TestClass
def method1
end
def method2
end
def method3
end
end
TestClass.methods.grep(/method1/) # => []
...
How can I change Mac OS's default Java VM returned from /usr/libexec/java_home
...'`"
But standard double-clickable application bundles don't use JDKs installed under /Library/Java at all. Old-style .app bundles using Apple's JavaApplicationStub will use Apple Java 6 from /System/Library/Frameworks, and new-style ones built with AppBundler without a bundled JRE will use the "p...
Merge 2 arrays of objects
..."lang", value: "German"}];
function mergeByProperty(arr1, arr2, prop) {
_.each(arr2, function(arr2obj) {
var arr1obj = _.find(arr1, function(arr1obj) {
return arr1obj[prop] === arr2obj[prop];
});
arr1obj ? _.extend(arr1obj, arr2obj) : arr1.push(arr2obj);
});
}
mergeByPropert...
Cross-Domain Cookies
...erver side you need to have the following headers:
header("Access-Control-Allow-Origin: http://origin.domain:port");
header("Access-Control-Allow-Credentials: true");
header("Access-Control-Allow-Methods: GET, POST");
header("Access-Control-Allow-Headers: Content-Type, *");
Within the PHP-file yo...
SVN needs-lock 设置强制只读属性（官方资料） - 环境配置 - 清泛IT论坛，...
...when the property is not available
sets the svn:needs-lock property on all already existing binary files in repositories
configures users to automatically set property svn:needs-lock on newly added binary files1) - create a pre-commit.cmd script in the repository\hooks directory. This script...
Selecting a row of pandas series/dataframe by integer index
... edited Jun 5 '18 at 12:40
marc_aragones
3,37644 gold badges2323 silver badges3333 bronze badges
answered Apr 19 '13 at 12:20
...
Why is a round-trip conversion via a string not safe for a double?
...ber(value, 17, &number);
DoubleToNumber is pretty simple -- it just calls _ecvt, which is in the C runtime:
void DoubleToNumber(double value, int precision, NUMBER* number)
{
WRAPPER_CONTRACT
_ASSERTE(number != NULL);
number->precision = precision;
if (((FPDOUBLE*)&val...
Is Big O(logn) log base e?
...nary search tree type of data structures, I see the Big O notation is typically noted as O(logn). With a lowercase 'l' in log, does this imply log base e (n) as described by the natural logarithm? Sorry for the simple question but I've always had trouble distinguishing between the different impli...