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Painless way to install a new version of R?
Andrew Gelman recently lamented the lack of an easy upgrade process for R (probably more relevant on Windows than Linux). Does anyone have a good trick for doing the upgrade, from installing the software to copying all the settings/packages over?
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How to use Active Support core extensions
I have Active Support 3.0.3 installed and Rails 3.0.3 with Ruby 1.8.7.
5 Answers
5
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Create a List of primitive int?
...atic conversion that the Java compiler makes
between the primitive types and their corresponding object wrapper
classes.
So the following is valid:
int myInt = 1;
List<Integer> list = new ArrayList<Integer>();
list.add(myInt);
System.out.println(list.get(0)); //prints 1
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How to run Unix shell script from Java code?
It is quite simple to run a Unix command from Java.
17 Answers
17
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what is the use of xsi:schemaLocation?
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The Java XML parser that spring uses will read the schemaLocation values and try to load them from the internet, in order to validate the XML file. Spring, in turn, intercepts those load requests and serves up versions from inside its own JAR files.
If you omit the schemaLocation, then the XML pa...
When to use Task.Delay, when to use Thread.Sleep?
...ed to avoid all of that overhead, maximize throughput, allow cancellation, and provide cleaner code.
– Corillian
May 3 '16 at 16:06
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Set line spacing
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Try the line-height property.
For example, 12px font-size and 4px distant from the bottom and upper lines:
line-height: 20px; /* 4px +12px + 4px */
Or with em units
line-height: 1.7em; /* 1em = 12px in this case. 20/12 == 1.666666 */
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What is the Ruby (spaceship) operator?
...en return -1
if a = b then return 0
if a > b then return 1
if a and b are not comparable then return nil
It's useful for sorting an array.
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how to find host name from IP with out login to the host
...s. When this option is used, there is no
need to provide the name, class and type arguments. dig automatically
performs a lookup for a name like 11.12.13.10.in-addr.arpa and sets
the query type and class to PTR and IN respectively.
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What does the caret (^) character mean?
...that git commits can have more than one parent. HEAD^ is short for HEAD^1, and you can also address HEAD^2 and so on as appropriate.
You can get to parents of any commit, not just HEAD. You can also move back through generations: for example, master~2 means the grandparent of the tip of the master ...