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Designing function f(f(n)) == -n
...turn n - 1
else:
return -1 * (n + 1)
Python automatically promotes integers to arbitrary length longs. In other languages the largest positive integer will overflow, so it will work for all integers except that one.
To make it work for real numbers you need to replace the n ...
JavaScript/regex: Remove text between parentheses
...the parentheses are in the middle of a string, the regex above will remove all the whitespace around them. This is probably not good.
– Nigel Johnson
Nov 13 '17 at 11:42
1
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Java Multiple Inheritance
...
@MoritzPetersen If you really want to go into reusing abstractions and giving meaningful names, probably AbstractEquidae would be more suitable than AbstractHorse. It would be strange to have a zebra extend an abstract horse. Nice answer, by the way....
How to handle both a single item and an array for the same property using JSON.net
....Categories));
Console.WriteLine();
}
}
}
And finally, here is the output of the above:
email: john.doe@sendgrid.com
timestamp: 1337966815
event: open
categories: newuser, transactional
email: jane.doe@sendgrid.com
timestamp: 1337966815
event: open
categories: olduser
F...
Keyboard Interrupts with python's multiprocessing Pool
...s to set up the worker processes to ignore SIGINT altogether, and confine all the cleanup code to the parent process. This fixes the problem for both idle and busy worker processes, and requires no error handling code in your child processes.
import signal
...
def init_worker():
signal.sign...
How to timeout a thread
... SSCCE:
package com.stackoverflow.q2275443;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
public clas...
Git Cherry-pick vs Merge Workflow
...f a commit identifies it not just in and of itself but also in relation to all other commits that precede it. This offers you a guarantee that the state of the repository at a given SHA1 is identical across all clones. There is (in theory) no chance that someone has done what looks like the same c...
How to add Options Menu to Fragment in Android
...
Call the super method:
Java:
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
}
@Override
public void onCreateOptio...
MongoDB: How to query for records where field is null or not set?
...ount({sent_at: {$exists: false}})
If its there and null, or not there at all:
db.emails.count({sent_at: null})
Refer here for querying and null
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You need to use a Theme.AppCompat theme (or descendant) with this activity
...a subclass, ActionBarActivity), to Activity, must also change the various calls with "support" to the corresponding call without "support". So, instead of getSupportFragmentManager, call getFragmentManager.
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