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Python circular importing?
...if you set them up correctly.
The easiest way to do so is to use import my_module syntax, rather than from my_module import some_object. The former will almost always work, even if my_module included imports us back. The latter only works if my_object is already defined in my_module, which in a cir...
Property getters and setters
...g to backup the computed property. Try this:
class Point {
private var _x: Int = 0 // _x -> backingX
var x: Int {
set { _x = 2 * newValue }
get { return _x / 2 }
}
}
Specifically, in the Swift REPL:
15> var pt = Point()
pt: Point = {
_x = 0
}
16> pt.x = 10...
Add Foreign Key to existing table
...
To add a foreign key (grade_id) to an existing table (users), follow the following steps:
ALTER TABLE users ADD grade_id SMALLINT UNSIGNED NOT NULL DEFAULT 0;
ALTER TABLE users ADD CONSTRAINT fk_grade_id FOREIGN KEY (grade_id) REFERENCES grades(id);
...
How do I configure different environments in Angular.js?
...nstant: {
options: {
name: 'config',
wrap: '"use strict";\n\n{%= __ngModule %}',
space: ' '
},
development: {
options: {
dest: '<%= yeoman.app %>/scripts/config.js'
},
constants: {
ENV: 'development'
}
},
production: {
options: {
des...
How can I quantify difference between two images?
...ead images as 2D arrays (convert to grayscale for simplicity)
img1 = to_grayscale(imread(file1).astype(float))
img2 = to_grayscale(imread(file2).astype(float))
# compare
n_m, n_0 = compare_images(img1, img2)
print "Manhattan norm:", n_m, "/ per pixel:", n_m/img1.size
print "Z...
What tools are there for functional programming in C?
...
FFCALL lets you build closures in C -- callback = alloc_callback(&function, data) returns a function pointer such that callback(arg1, ...) is equivalent to calling function(data, arg1, ...). You will have to handle garbage collection manually, though.
Relatedly, blocks have...
How can I get the MAC and the IP address of a connected client in PHP?
...
Server IP
You can get the server IP address from $_SERVER['SERVER_ADDR'].
Server MAC address
For the MAC address, you could parse the output of netstat -ie in Linux, or ipconfig /all in Windows.
Client IP address
You can get the client IP from $_SERVER['REMOTE_ADDR']
C...
Is it possible to use argsort in descending order?
... this method is that ids is a view of avgDists:
>>> ids.flags
C_CONTIGUOUS : False
F_CONTIGUOUS : False
OWNDATA : False
WRITEABLE : True
ALIGNED : True
UPDATEIFCOPY : False
(The 'OWNDATA' being False indicates this is a view, not a copy)
Another way to do this is something ...
How do I clone a Django model instance object and save it to the database?
...imary key of your object and run save().
obj = Foo.objects.get(pk=<some_existing_pk>)
obj.pk = None
obj.save()
If you want auto-generated key, set the new key to None.
More on UPDATE/INSERT here.
Official docs on copying model instances: https://docs.djangoproject.com/en/2.2/topics/db/que...
Python: Get relative path from comparing two absolute paths
.... if one of the paths is a common ancestor:
paths = […, …, …]
common_prefix = os.path.commonprefix(list_of_paths)
if common_prefix in paths:
…
You can then find the relative paths:
relative_paths = [os.path.relpath(path, common_prefix) for path in paths]
You can even handle more th...