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How can I calculate the difference between two dates?
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Not all days have 86400 seconds. For a trivial example that's fine but it's not a good idea in the real world. DST changes, leap seconds, etc can all mess with it. NSCalendar can tell you how many seconds are in a given day.
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How to print matched regex pattern using awk?
...search for pattern using //, then print out the line, which by default is called a record, denoted by $0. At least read up the documentation.
If you only want to get print out the matched word.
awk '{for(i=1;i<=NF;i++){ if($i=="yyy"){print $i} } }' file
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iOS - Dismiss keyboard when touching outside of UITextField
...TapGestureRecognizer(target: self, action: #selector(self.dismissKeyboard (_:)))
self.view.addGestureRecognizer(tapGesture)
For dismissKeyboard
@objc func dismissKeyboard (_ sender: UITapGestureRecognizer) {
aTextField.resignFirstResponder()
}
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Replace tabs with spaces in vim
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What this all means, is nicely explained on the Vim wiki.
– Serge Stroobandt
Dec 11 '16 at 1:43
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Is Java Regex Thread Safe?
...41681.html#A14 : "The Java 2 SDK, Standard Edition itself contains a file called src.zip that contains the source code for the public classes in the java package") so one can take a quick peek oneself.
– David Tonhofer
Nov 18 '13 at 15:40
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Fastest check if row exists in PostgreSQL
...f a single row from the batch exists in the table because then I know they all were inserted.
8 Answers
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Is it good style to explicitly return in Ruby?
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Was this meant to be a function that returned a value, or not? It's really hard to say what the developer meant, as it both assigns the instance variable, AND returns the value assigned as well.
Suppose much later, another programmer (perhaps not that familiar with how Ruby does returns based ...
How to print number with commas as thousands separators?
...For Python ≥3.6
Locale aware
import locale
locale.setlocale(locale.LC_ALL, '') # Use '' for auto, or force e.g. to 'en_US.UTF-8'
'{:n}'.format(value) # For Python ≥2.7
f'{value:n}' # For Python ≥3.6
Reference
Per Format Specification Mini-Language,
The ',' option signals the use ...
How to save/restore serializable object to/from file?
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No need to call the close method on a reader within your using block. Dispose() is implicit and will take place even if an exception is raised within the block before the explicit Close(). Very useful block of code.
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What's the u prefix in a Python string?
... Mar 17 '10 at 18:45
Stefan KendallStefan Kendall
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