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How to wait until an element exists?
...ionObserver((mutations) => {
mutations.forEach((mutation) => {
if (!mutation.addedNodes) return
for (let i = 0; i < mutation.addedNodes.length; i++) {
// do things to your newly added nodes here
let node = mutation.addedNodes[i]
}
})
})
observer.observe(documen...
How to calculate number of days between two given dates?
If I have two dates (ex. '8/18/2008' and '9/26/2008' ), what is the best way to get the number of days between these two dates?
...
Java default constructor
... you tell me which one of the following is a default constructor and what differentiates it from any other constructor?
13 ...
Which is better option to use for dividing an integer number by 2?
...
Use the operation that best describes what you are trying to do.
If you are treating the number as a sequence of bits, use bitshift.
If you are treating it as a numerical value, use division.
Note that they are not exactly equivalent. They can give different results for negative integers...
Check whether a cell contains a substring
Is there an in-built function to check if a cell contains a given character/substring?
9 Answers
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Is this a “good enough” random algorithm; why isn't it used if it's faster?
...
Your QuickRandom implementation hasn't really an uniform distribution. The frequencies are generally higher at the lower values while Math.random() has a more uniform distribution. Here's a SSCCE which shows that:
package com.stackoverflow.q14491966;
import java.util.Arrays...
Show/hide 'div' using JavaScript
...// Show
element.style.display = 'inline-block'; // Show
Alternatively, if you would still like the element to occupy space (like if you were to hide a table cell), you could change the element's visibility property instead:
element.style.visibility = 'hidden'; // Hide
element.style.visibil...
How can I check if multiplying two numbers in Java will cause an overflow?
...
If a and b are both positive then you can use:
if (a != 0 && b > Long.MAX_VALUE / a) {
// Overflow
}
If you need to deal with both positive and negative numbers then it's more complicated:
long maximum = Lo...
Where is Java's Array indexOf?
...e are a couple of ways to accomplish this using the Arrays utility class.
If the array is not sorted and is not an array of primitives:
java.util.Arrays.asList(theArray).indexOf(o)
If the array is primitives and not sorted, one should use a solution offered by one of the other answers such as Ke...
iOS: Use a boolean in NSUserDefaults
...ults standardUserDefaults] synchronize];
and read it by using this code:
if(![[NSUserDefaults standardUserDefaults] boolForKey:@"logged_in"]) {
[self displayLogin];
} else {
[self displayMainScreen];
}
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