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What is the colon operator in Ruby?
...bols have the distinct feature that any two symbols named the same will be identical:
"foo".equal? "foo" # false
:foo.equal? :foo # true
This makes comparing two symbols really fast (since only a pointer comparison is involved, as opposed to comparing all the characters like you would in a st...
How do I avoid capturing self in blocks when implementing an API?
...Complete];
}
The __block keyword marks variables that can be modified inside the block (we're not doing that) but also they are not automatically retained when the block is retained (unless you are using ARC). If you do this, you must be sure that nothing else is going to try to execute the block ...
How to remove the border highlight on an input text element
...
In your case, try:
input.middle:focus {
outline-width: 0;
}
Or in general, to affect all basic form elements:
input:focus,
select:focus,
textarea:focus,
button:focus {
outline: none;
}
In the comments, Noah Whitmore suggested taking thi...
CSS: How to have position:absolute div inside a position:relative div not be cropped by an overflow:
...ext/css">
/* Positioning */
#box1 { overflow: hidden }
#box2 { position: absolute }
#box3 { position: absolute; top: 10px }
/* Styling */
#box1 { background: #efe; padding: 5px; width: 125px }
#box2 { background...
Can't access object property, even though it shows up in a console log
...ess, but on the very next line of code, I can't access it with config.col_id_3 (see the "undefined" in the screenshot?). Can anyone explain this? I can get access to every other property except field_id_4 as well.
...
Generate a random number in the range 1 - 10
Since my approach for a test query which I worked on in this question did not work out, I'm trying something else now. Is there a way to tell pg's random() function to get me only numbers between 1 and 10?
...
How to select the row with the maximum value in each group
...
A dplyr solution:
library(dplyr)
ID <- c(1,1,1,2,2,2,2,3,3)
Value <- c(2,3,5,2,5,8,17,3,5)
Event <- c(1,1,2,1,2,1,2,2,2)
group <- data.frame(Subject=ID, pt=Value, Event=Event)
group %>%
group_by(Subject) %>%
summarize(max.pt = max(...
@ variables in Ruby on Rails
... and title ? Since both of them can be variable names. Also, how do I decide which kind of variable I should use? With @ or not?
...
What is the advantage of using REST instead of non-REST HTTP?
...ons about how to use HTTP . I wonder which advantage these conventions provide. Does anyone know?
14 Answers
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MySQL Select all columns from one table and some from another table
....
SELECT table1.*, table2.col1, table2.col3 FROM table1 JOIN table2 USING(id)
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