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When to use single quotes, double quotes, and backticks in MySQL
...write queries. I also understand the importance of being consistent. Until now, I have randomly used single quotes, double quotes, and backticks without any real thought.
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How does JavaScript .prototype work?
... really got my head around this prototype-based programming, does any one know how this works?
26 Answers
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Build unsigned APK file with Android Studio
I'm developing an android app with the Android Developer Tool.
Now I tried the new Android Studio, everything works fine if connect my smartphone with the pc and directly run the program in the Android Studio.
But now I want to test the program with other smartphones without connecting them to my pc...
mongodb: insert if not exists
... specify what data you want to write:
data = {"$set":{"key2":"value2"}}
Now your selected document will update the value of "key2" only and leave everything else untouched.
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What is the best IDE to develop Android apps in? [closed]
...S
Android Studio has officially come out of beta and been released. It is now the official IDE for Android Development - Eclipse won't be supported anymore. It is definitely the IDE of choice for Android Development. Link to download page: http://developer.android.com/sdk/index.html
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When to use volatile with multi threading?
...e semantics on volatile variables.
[Update for C++11]
The C++11 Standard now does acknowledge multithreading directly in the memory model and the lanuage, and it provides library facilities to deal with it in a platform-independant way. However the semantics of volatile still have not changed. v...
Date ticks and rotation in matplotlib
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import numpy as np
import matplotlib.pyplot as plt
import datetime as dt
now = dt.datetime.now()
hours = [now + dt.timedelta(minutes=x) for x in range(0,24*60,10)]
days = [now + dt.timedelta(days=x) for x in np.arange(0,30,1/4.)]
hours_value = np.random.random(len(hours))
days_value = np.random.ra...
Adding days to a date in Python
...ng it is a dumb idea? What is datetime? You can't rely on convention to know, but always have to look at the imports.
– Xiong Chiamiov
Jun 5 '17 at 17:47
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Count number of days between two dates
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Doesn't work for (Time.zone.now.to_date - 23.hours.ago.to_date).to_i, it gives 1 and should be 0
– Yuri Ghensev
Feb 4 '17 at 16:21
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How do I get the time difference between two DateTime objects using C#?
... classs Subtract method, which returns a TimeSpan.
var dateOne = DateTime.Now;
var dateTwo = DateTime.Now.AddMinutes(-5);
var diff = dateTwo.Subtract(dateOne);
var res = String.Format("{0}:{1}:{2}", diff.Hours,diff.Minutes,diff.Seconds));
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