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List of zeros in python [duplicate]
... to same id. This is not a problem with immutable objects like integers or strings but if you try to create list of mutable objects like a list of lists ([[]] * n) then all the elements will refer to the same object.
a = [[]] * 10
a[0].append(1)
a
> [[1], [1], [1], [1], [1], [1], [1], [1], [1],...
HashMap with multiple values under the same key
...ide.
Examples
1. Map with list as the value
// create our map
Map<String, List<Person>> peopleByForename = new HashMap<>();
// populate it
List<Person> people = new ArrayList<>();
people.add(new Person("Bob Smith"));
people.add(new Person("Bob Jones"));
peopl...
What's a correct and good way to implement __hash__()?
... studied a wide variety of hash functions. He told me that
for c in some_string:
hash = 101 * hash + ord(c)
worked surprisingly well for a wide variety of strings. I've found that similar polynomial techniques work well for computing a hash of disparate subfields.
...
How to update SQLAlchemy row entry?
...thanks for your answer, instead of an int variable i am trying do update a string variable, how do i do that ? i am using an sqlite database and the variables i want to change are in current_user, through submitting a form
– dani bilel
May 20 at 4:33
...
Finding the Eclipse Version Number
...uring out the version of eclipse\plugins\org.eclipse.platform_ plugin
String platformFile = <the above file>; //actually directory
versionPattern = Pattern.compile("\\d\\.\\d\\.\\d");
Matcher m = versionPattern.matcher(platformFile);
return m.group();
...
Adding a new array element to a JSON object
... parse it so you can apply the changes to a native JavaScript Object, then stringify back to JSON
var jsonStr = '{"theTeam":[{"teamId":"1","status":"pending"},{"teamId":"2","status":"member"},{"teamId":"3","status":"member"}]}';
var obj = JSON.parse(jsonStr);
obj['theTeam'].push({"teamId":"4","sta...
What is the purpose of python's inner classes?
... methods of the outer class — they will see the outer's self without any extra work required (just use a different identifier where you would typically put the inner's self; like innerself), and will be able to access the outer instance via that.
– Evgeni Sergeev
...
How do the Proxy, Decorator, Adapter, and Bridge Patterns differ?
... but also abstraction. It adds one more indirection to the delegation. The extra delegation is the bridge. It decouples Adapter even from adapting interface. It increases complexity more than any other of the other wrapping patterns, so apply with care.
Differences in constructors
Pattern differen...
Better way to check variable for null or empty string?
...tion (present and neither empty nor only white space
function IsNullOrEmptyString($str){
return (!isset($str) || trim($str) === '');
}
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C/C++ with GCC: Statically add resource files to executable/library
...This works, because a) Most executable image formats don't care if there's extra data behind the image and b) zip stores the file signature at the end of the zip file. This means, your executable is a regular zip file after this (except for your upfront executable, which zip can handle), which can b...