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Correctly determine if date string is a valid date in that format
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If you are using PHP 5.2.x, you should use strtotime to get the unix timestamp then date('Y-m-d', $t) to get the string date. Then you compare them just like this answer.
– pedromanoel
J...
do..end vs curly braces for blocks in Ruby
...-line blocks and curly braces for single line blocks, but there is also a difference between the two that can be illustrated with this example:
puts [1,2,3].map{ |k| k+1 }
2
3
4
=> nil
puts [1,2,3].map do |k| k+1; end
#<Enumerator:0x0000010a06d140>
=> nil
This means that {} has a high...
close vs shutdown socket?
In C, I understood that if we close a socket, it means the socket will be destroyed and can be re-used later.
9 Answers
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Test if string is a number in Ruby on Rails
...is_number? Method.
Create a helper method:
def is_number? string
true if Float(string) rescue false
end
And then call it like this:
my_string = '12.34'
is_number?( my_string )
# => true
Extend String Class.
If you want to be able to call is_number? directly on the string instead of pa...
Javascript: best Singleton pattern [duplicate]
...rsion
class Singleton {
static instance;
constructor() {
if (instance) {
return instance;
}
this.instance = this;
}
foo() {
// ...
}
}
console.log(new Singleton() === new Singleton());
(2) ES6 Version
class Singleton {
const...
Determine whether JSON is a JSONObject or JSONArray
...ich it will be. I need to work with the JSON, but to do so, I need to know if it is an Object or an Array.
8 Answers
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How to check if AlarmManager already has an alarm set?
When my app starts, I want it to check if a particular alarm (registered via AlarmManager) is already set and running. Results from google seem to indicate that there is no way to do this. Is this still correct? I need to do this check in order to advise the user before any action is taken to create...
How to detect if my shell script is running through a pipe?
How do I detect from within a shell script if its standard output is being sent to a terminal or if it's piped to another process?
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Fragment onResume() & onPause() is not called on backstack
...They are tightly coupled to the Activity.
Read the Handling the Fragment Lifecycle section of this article.
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How to get a variable value if variable name is stored as string?
How can I retrieve a bash variable value if I have the variable name as string?
7 Answers
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