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Pass a data.frame column name to a function
...l_name,col1,col2){
df$col_name <- df$col1 + df$col2
df
}
#Call foo() like this:
foo(dat,z,x,y)
The problem here is that df$col1 doesn't evaluate the expression col1. It simply looks for a column in df literally called col1. This behavior is described in ?Extract under the secti...
Determine which element the mouse pointer is on top of in JavaScript
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DEMO
There's a really cool function called document.elementFromPoint which does what it sounds like.
What we need is to find the x and y coords of the mouse and then call it using those values:
var x = event.clientX, y = event.clientY,
...
Convert stdClass object to array in PHP
...ncode($object), true);
Or if you prefer, you can traverse the object manually, too:
foreach ($object as $value)
$array[] = $value->post_id;
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Trying to mock datetime.date.today(), but not working
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There are a few problems.
First of all, the way you're using mock.patch isn't quite right. When used as a decorator, it replaces the given function/class (in this case, datetime.date.today) with a Mock object only within the decorated function. So, only within...
How to use arguments from previous command?
... the previous commands (arg 0). Similarly Alt-- then repeating Alt-. would allow you to step through the previous next-to-last arguments.
If there is no appropriate argument on a particular line in history, the bell will be rung.
If there is a particular combination you use frequently, you can def...
Using {} in a case statement. Why?
What is the point with using { and } in a case statement? Normally, no matter how many lines are there in a case statement, all of the lines are executed. Is this just a rule regarding older/newer compilers or there is something behind that?
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What does gcc's ffast-math actually do?
...tside of IEEE standards, but I can't seem to find information on what is really happening when it's on. Can anyone please explain some of the details and maybe give a clear example of how something would change if the flag was on or off?
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What's the difference between Spring Data's MongoTemplate and MongoRepository?
...goRepository but struggled with complex queries to find examples or to actually understand the Syntax.
3 Answers
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Call one constructor from another
...will be executed first then it will get back to the string version? (Like calling super() in Java?)
– Rosdi Kasim
Dec 18 '13 at 16:49
21
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“where 1=1” statement [duplicate]
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It's usually when folks build up SQL statements.
When you add and value = "Toyota" you don't have to worry about whether there is a condition before or just WHERE. The optimiser should ignore it
No magic, just practical
Example ...