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Remove all the elements that occur in one list from another
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Python has a language feature called List Comprehensions that is perfectly suited to making this sort of thing extremely easy. The following statement does exactly what you want and stores the result in l3:
l3 = [x for x in l1 if x not in l2]
l3 will c...
Differences between strong and weak in Objective-C
...er the case, the object gets destroyed and your weak property will automatically get set to nil. The most frequent use cases of weak references in iOS are:
delegate properties, which are often referenced weakly to avoid retain cycles, and
subviews/controls of a view controller's main view because ...
How to run a shell script at startup
On an Amazon S3 Linux instance, I have two scripts called start_my_app and stop_my_app which start and stop forever (which in turn runs my Node.js application). I use these scripts to manually start and stop my Node.js application. So far so good.
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How can I kill a process by name instead of PID?
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A bit longer alternative:
kill `pidof firefox`
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Parsing a JSON string in Ruby
...s looks like JavaScript Object Notation (JSON). You can parse JSON that resides in some variable, e.g. json_string, like so:
require 'json'
JSON.parse(json_string)
If you’re using an older Ruby, you may need to install the json gem.
There are also other implementations of JSON for Ruby that ...
How to select distinct rows in a datatable and store into an array
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Following single line of code will avoid the duplicate rows of a DataTable:
dataTable.DefaultView.ToTable(true, "employeeid");
Where:
first parameter in ToTable() is a boolean which indicates whether you want distinct rows or not.
second parameter in the ToT...
UITextField auto-capitalization type - iPhone App
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It doesn't work, i tried it on Xcode 6 iOS 8 Swift. I did it in code and interface builder, neither works.
– Van Du Tran
Nov 27 '14 at 21:26
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Generating random number between 1 and 10 in Bash Shell Script [duplicate]
...re should be a fair draw from numbers 0 to 32767, but because you can't divide that evenly into groups of 10, there is a very small bias against 9 and 10 in this implementation. Most people shouldn't need to worry about this, because you shouldn't be using $RANDOM for security purposes anyway.
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How do I watch a file for changes?
...this on a Linux box, I'm seeing that the directory_changed method is being called, but not file_changed.
– Ken Kinder
Nov 22 '12 at 19:08
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How do shift operators work in Java? [duplicate]
...es, shifting is shorter/more efficient than converting an int to a double, calling Math.pow() and converting back to an int.) It's also useful for transforming an int value from signed (Java) to an unsigned equivalent (C/C++; Java doesn't have unsigned types, which is one of its shortcomings).
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