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How do I merge two dictionaries in a single expression in Python (taking union of dictionaries)?
...z = {**x, **y}
In Python 2, (or 3.4 or lower) write a function:
def merge_two_dicts(x, y):
z = x.copy() # start with x's keys and values
z.update(y) # modifies z with y's keys and values & returns None
return z
and now:
z = merge_two_dicts(x, y)
In Python 3.9.0a4 or greater...
How to add 'ON DELETE CASCADE' in ALTER TABLE statement
...t instead of modify constraint.
Now this is the command:
ALTER TABLE child_table_name
ADD CONSTRAINT fk_name
FOREIGN KEY (child_column_name)
REFERENCES parent_table_name(parent_column_name)
ON DELETE CASCADE;
s...
Optional Parameters in Go?
...amp;Foobar{}
// ... (write initializations with default values)...
for _, op := range options{
err := op(fb)
if err != nil {
return nil, err
}
}
return fb, nil
}
where each option is a function which mutates the Foobar. Then provide convenient ways for your user to use or...
How to explain callbacks in plain english? How are they different from calling one function from ano
...n the call-back-function for further processing. example: func1(a, callback_func){ v = a + 1} and there is predefined call back function: callback_func(v){return v+1;} this will increase a by 2, so if you pass argument of integer 4 in "a" parameter, the callback_funct will return 6 as result. Read t...
Is a URL allowed to contain a space?
...s separated by a white space. If you put a space in your url:
GET /url end_url HTTP/1.1
You know have 4 fields, the HTTP server will tell you it is an invalid request.
GET /url%20end_url HTTP/1.1
3 fields => valid
Note: in the query string (after ?), a space is usually encoded as a +
GET ...
Is there an easy way to add a border to the top and bottom of an Android View?
...move the solid if you don't want a fill. The set background="@drawable/your_shape_drawable" on your layout/view.
Option 2: Background View
Here's a little trick I've used in a RelativeLayout. Basically you have a black square under the view you want to give a border, and then give that view some p...
JsonMappingException: No suitable constructor found for type [simple type, class ]: can not instanti
...roperly. See exlanation here: cowtowncoder.com/blog/archives/2010/08/entry_411.html
– jpennell
Feb 14 '13 at 1:35
...
Locking pattern for proper use of .NET MemoryCache
...of C# In a Nutshell discusses this here, albahari.com/threading/part2.aspx#_MonitorEnter_and_MonitorExit
– BrutalSimplicity
May 12 '18 at 15:27
9
...
How can I delete a service in Windows?
...or a more concise list, execute this command:
SC QUERY state= all | FIND "_NAME"
The short service name will be listed just above the display name, like this:
SERVICE_NAME: MyService
DISPLAY_NAME: My Special Service
And thus to delete that service:
SC STOP MyService
SC DELETE MyService
...
Add line break to 'git commit -m' from the command line
... rsy$ bash --version GNU bash, version 3.2.53(1)-release (x86_64-apple-darwin13) Copyright (C) 2007 Free Software Foundation, Inc. The output of that command is, as expected, shown in two different lines!
– ccoutinho
Jun 2 '15 at 21:49
...