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What is the colon operator in Ruby?
..." # 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 string), plus you won't have a zillion copies of the same symbol floating about.
Also, unlike strings, sy...
Memory management in Qt?
... need to delete and/or destroy my objects? Is any of this handled automatically?
4 Answers
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How do I test for an empty JavaScript object?
...do you post answer including jQuery if the question is not about jQuery at all?
– Eru
Oct 1 '12 at 14:10
48
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Spring @PropertySource using YAML
Spring Boot allows us to replace our application.properties files with YAML equivalents. However I seem to hit a snag with my tests. If I annotate my TestConfiguration (a simple Java config), it is expecting a properties file.
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What is the preferred/idiomatic way to insert into a map?
...
First of all, operator[] and insert member functions are not functionally equivalent :
The operator[] will search for the key, insert a default constructed value if not found, and return a reference to which you assign a value. Obvi...
Unable to create/open lock file: /data/mongod.lock errno:13 Permission denied
How to I get mongo to use a mounted drive on ec2? I really do not understand. I attached a volume on ec2 formatted the drive as root and start as root and yet as root I cant access? I am running on ubuntu 12.04. No other mongo is running
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Regular Expression to get a string between parentheses in Javascript
...eses, grab Group 1 value.
Most up-to-date JavaScript code demo (using matchAll):
const strs = ["I expect five hundred dollars ($500).", "I expect.. :( five hundred dollars ($500)."];
const rx = /\(([^()]*)\)/g;
strs.forEach(x => {
const matches = [...x.matchAll(rx)];
console.log( Array.fr...
bash HISTSIZE vs. HISTFILESIZE?
... is ongoing.
HISTFILESIZE is the number of lines or commands that (a) are allowed in the history file at startup time of a session, and (b) are stored in the history file at the end of your bash session for use in future sessions.
Notice the distinction between file: on disk - and list: in memory....
Merge two (or more) lists into one, in C# .NET
...
You can use the LINQ Concat and ToList methods:
var allProducts = productCollection1.Concat(productCollection2)
.Concat(productCollection3)
.ToList();
Note that there are more efficient ways to do this -...
Get a specific bit from byte
I have a byte, specifically one byte from a byte array which came in via UDP sent from another device. This byte stores the on/off state of 8 relays in the device.
...