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How to use a variable to specify column name in ggplot
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If for whatever reason you'd rather not use aes_string, you could change it to (the somewhat more cumbersome):
ggplot( rates.by.groups, aes(x=name, y=rate, colour= get(column),
group=get(column) ) )
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What's wrong with foreign keys?
... a foreign key (if I remember correctly). However, to me they seem pretty vital to avoid duplication and subsequent data integrity problems throughout your database.
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UTF-8 all the way through
...and retrieve values encoded natively in UTF-8. Note that MySQL will implicitly use utf8mb4 encoding if a utf8mb4_* collation is specified (without any explicit character set).
In older versions of MySQL (< 5.5.3), you'll unfortunately be forced to use simply utf8, which only supports a subset o...
How to list the files inside a JAR file?
...e == null)
break;
String name = e.getName();
if (name.startsWith("path/to/your/dir/")) {
/* Do something with this entry. */
...
}
}
}
else {
/* Fail... */
}
Note that in Java 7, you can create a FileSystem from the JAR (zip) file, and then use NIO's directory wa...
When to use EntityManager.find() vs EntityManager.getReference() with JPA
I have come across a situation (which I think is weird but is possibly quite normal) where I use the EntityManager.getReference(LObj.getClass(), LObj.getId()) to get a database entity and then pass the returned object to be persisted in another table.
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Is embedding background image data into CSS as Base64 good or bad practice?
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It's not a good idea when you want your images and style information to be cached separately. Also if you encode a large image or a significant number of images in to your css file it will take the browser longer to download...
Can an abstract class have a constructor?
...n the parent
abstract class, the constructor used in subclass must explicitly call
the parent constructor.
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How do I disable a Pylint warning?
..."more than one statement on a single line" -- I often put if statements with short single-line results on the same line), in Pylint 0.21.1 (if it matters: astng 0.20.1, common 0.50.3, Python 2.6.6 (r266:84292, Sep 15 2010, 16:22:56)).
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How do I detect that an iOS app is running on a jailbroken phone?
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It depends what you mean by jailbreak. In the simple case, you should be able to see if Cydia is installed and go by that - something like
NSString *filePath = @"/Applications/Cydia.app";
if ([[NSFileManager defaultManager]...
Variable's scope in a switch case [duplicate]
I think I don't understand how the scope works in a switch case.
7 Answers
7
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