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Make sure only a single instance of a program is running
...ify_lock')
except socket.error as e:
error_code = e.args[0]
error_string = e.args[1]
print "Process already running (%d:%s ). Exiting" % ( error_code, error_string)
sys.exit (0)
The unique string postconnect_gateway_notify_lock can be changed to allow multiple programs that need...
Why doesn't java.lang.Number implement Comparable? [duplicate]
...programmers could override. This is no excuse. The same problem exists for Strings when it comes to empty strings or null references. Is a null reference greater than or less than the string "foo"? Sun picked an ordering that makes sense.
– Jason
Dec 2 '15 at 1...
How to execute a raw update sql with dynamic binding in rails
...
ActiveRecord::Base.connection has a quote method that takes a string value (and optionally the column object). So you can say this:
ActiveRecord::Base.connection.execute(<<-EOQ)
UPDATE foo
SET bar = #{ActiveRecord::Base.connection.quote(baz)}
EOQ
Note if you're in a Ra...
What do all of Scala's symbolic operators mean?
...nds
<? <! // Start token for various XML elements
" """ // Strings
' // Indicate symbols and characters
@ // Annotations and variable binding on pattern matching
` // Denote constant or enable arbitrary identifiers
, // Parameter separator
; ...
Pickle or json?
...
The benchmark cited by @mac only tests strings. I tested str, int and float seperately and found out that json is slower than cPickle with float serialization, but faster with float unserialization. For int (and str), json is faster both ways. Data and code: gist....
How to write a simple Html.DropDownListFor()?
...ass:
public class Color
{
public int ColorId { get; set; }
public string Name { get; set; }
}
And let's say that you have the following model:
public class PageModel
{
public int MyColorId { get; set; }
}
And, finally, let's say that you have the following list of colors. They coul...
Setting HttpContext.Current.Session in a unit test
... var httpRequest = new HttpRequest("", "http://example.com/", "");
var stringWriter = new StringWriter();
var httpResponse = new HttpResponse(stringWriter);
var httpContext = new HttpContext(httpRequest, httpResponse);
var sessionContainer = new HttpSessionStateContainer("id", new S...
How to get key names from JSON using jq
... cat input.json | jq -r 'keys'
From jq help:
-r output raw strings, not JSON texts;
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Change type of varchar field to integer: “cannot be cast automatically to type integer”
...y this, it will work for sure.
When writing Rails migrations to convert a string column to an integer you'd usually say:
change_column :table_name, :column_name, :integer
However, PostgreSQL will complain:
PG::DatatypeMismatch: ERROR: column "column_name" cannot be cast automatically to type i...
How to make an element in XML schema optional?
...
Try this
<xs:element name="description" type="xs:string" minOccurs="0" maxOccurs="1" />
if you want 0 or 1 "description" elements, Or
<xs:element name="description" type="xs:string" minOccurs="0" maxOccurs="unbounded" />
if you want 0 to infinity number of "de...