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List comprehension: Returning two (or more) items for each item
...bda x: x + 2
>>> g = lambda x: x ** 2
>>> list(chain.from_iterable((f(x), g(x)) for x in range(3)))
[2, 0, 3, 1, 4, 4]
Timings:
from timeit import timeit
f = lambda x: x + 2
g = lambda x: x ** 2
def fg(x):
yield f(x)
yield g(x)
print timeit(stmt='list(chain.from_itera...
How to change the name of a Django app?
...ls.py , 'manage.py' , and settings.py files.
Edit the database table django_content_type with the following command: UPDATE django_content_type SET app_label='<NewAppName>' WHERE app_label='<OldAppName>'
Also if you have models, you will have to rename the model tables. For postgres use...
Using custom std::set comparator
...overloads the () operator so it can be called like a function).
struct lex_compare {
bool operator() (const int64_t& lhs, const int64_t& rhs) const {
stringstream s1, s2;
s1 << lhs;
s2 << rhs;
return s1.str() < s2.str();
}
};
You then...
Javascript “this” pointer within nested function
...
@Arashsoft this in this.doSomeEffects() points to std_obj. As explained in the answer above if a function doesn't have object reference then it takes this to be a window object.
– Shivam
Jun 28 '19 at 18:46
...
How do I check if a string contains another string in Swift?
... and containsIgnoringCase for String
extension String {
func contains(_ find: String) -> Bool{
return self.range(of: find) != nil
}
func containsIgnoringCase(_ find: String) -> Bool{
return self.range(of: find, options: .caseInsensitive) != nil
}
}
Older Swift vers...
Stop “developer tools access needs to take control of another process for debugging to continue” ale
...ict>
- <key>group</key>
- <string>_developer</string>
<key>shared</key>
<true/>
- <key>timeout</key>
- <integer>36000</integer>
+ <key>k-of-n</key&g...
Rails 3 execute custom sql query without a model
...
Maybe try this:
ActiveRecord::Base.establish_connection(...)
ActiveRecord::Base.connection.execute(...)
share
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...
Python: reload component Y imported with 'from X import Y'?
... This doesn't seem to work always. I have a module Foo which has an __init__.py that fetches a submodule... I'll post an answer as a counterexample.
– Jason S
Oct 17 '17 at 22:32
...
Weak and strong property setter attributes in Objective-C
...n release autorelease etc... Instead you use strong weak for properties or __strong
__weak
for variables (defaults to __strong). Strong is the equivalent to retain, however ARC will manage the release for you.
The only time you would want to use weak, is if you wanted to avoid retain cycles (e.g...
How to do what head, tail, more, less, sed do in Powershell? [closed]
...txt | more # or less if you have it installed
gc log.txt | %{ $_ -replace '\d+', '($0)' } # sed
This works well enough for small files, larger ones (more than a few MiB) are probably a bit slow.
The PowerShell Community Extensions include some cmdlets for specialised file stuf...