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What does the “===” operator do in Ruby? [duplicate]
...hen clause of a case statement. In other languages, the above is true.
To my knowledge, Ruby doesn't have true operators, they are all methods which are invoked on the LHS of the expression, passing in the RHS of the expression.
So, really, you could override any "operator" you want in your classe...
How do I prevent commands from showing up in Bash history?
...ht, just with a single Arrow-Up + Enter :)
I put the following snippet in my init file (works with .zshrc, should also work with .bashrc)
# ...
HISTFILE=~/.zshhistory
# ...
# remove dangerous entries from the shell history
temp_histfile="/tmp/$$.temp_histfile"
grep -v -P '^rm .*-rf' $HISTFILE >...
What is an existential type?
...whatever type you want, I don't need to know anything about the type to do my job, I'll only refer to it opaquely as X.
When someone defines an existential type ∃X they're saying: I'll use whatever type I want here; you wont know anything about the type, so you can only refer to it opaquely as X....
How to run Rails console in the test environment and load test_helper.rb?
...s. And, you do need to load at least some parts of your environment -- in my case features/support/helpers.rb wasn't automagically loaded. Also, Rack::Test isn't loaded.
– Derrell Durrett
Nov 16 '16 at 0:08
...
Find where python is installed (if it isn't default dir)
Python is on my machine, I just don't know where, if I type python in terminal it will open Python 2.6.4, this isn't in it's default directory, there surely is a way of finding it's install location from here?
...
jQuery Event Keypress: Which key was pressed?
... Hmm, it looks like it's an IE specific property. It works for my app in IE but not Chrome. Guess I'm using keycode.
– Kevin
Feb 8 '13 at 0:47
Python division
... when you typecast.
Example:
Since this is a question that always pops in my head when I am doing arithmetic operations (should I convert to float and which number), an example from that aspect is presented:
>>> a = 1/2/3/4/5/4/3
>>> a
0
When we divide integers, not surprisingl...
Play/pause HTML 5 video using JQuery
...I managed to make it work:
jQuery( document ).ready(function($) {
$('.myHTMLvideo').click(function() {
this.paused ? this.play() : this.pause();
});
});
All my HTML5 tags have the class 'myHTMLvideo'
shar...
Difference between JOIN and INNER JOIN
...use INNER JOIN, but rather I just use "JOIN":
SELECT ColA, ColB, ...
FROM MyTable AS T1
JOIN MyOtherTable AS T2
ON T2.ID = T1.ID
LEFT OUTER JOIN MyOptionalTable AS T3
ON T3.ID = T1.ID
share
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Is it possible to GROUP BY multiple columns using MySQL?
Is it possible to GROUP BY more than one column in a MySQL SELECT query? For example:
7 Answers
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