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Index on multiple columns in Ruby on Rails
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The order does matter in indexing.
Put the most selective field first, i.e. the field that narrows down the number of rows fastest.
The index will only be used insofar as you use its columns in sequence starting at the beginning. i.e. if you index on [:user_id, :article_id...
Is there a JavaScript MVC (micro-)framework? [closed]
...n excellent solution. It's everything is a plugin approach enables you to select only the features you need. As of 2.0, it's based on jQuery.
On progressively enhancing your website, that's left up to the user as JMVC provides just a middle layer for development - it's up to you to make that de...
How can I pass a Bitmap object from one activity to another
...Intent(context, AudioService::class.java).apply {
action = CONTENT_SELECTED_ACTION
putExtra(CONTENT_SELECTED_BITMAP_KEY, contentPlayer.image)
})
3. Convert ByteArray back to Bitmap.
Utils.kt
fun ByteArray.byteArrayToBitmap(context: Context) =
run {
BitmapFactory.d...
How to add items to a spinner in Android?
...d:id="@+id/spinner"
android:layout_width="fill_parent"
android:drawSelectorOnTop="true"
android:prompt="@string/spin"
android:entries="@array/spinnerItems"
/>
Items definition in the file array.xml:
<resources>
<string-array name="spinnerItems">
<item...
what is the most efficient way of counting occurrences in pandas?
...].astype('str').stack().value_counts().sum() which equates to setting each selected column to str type, stacking all individual columns on top, forming basically one column and then doing the value_counts() and sum() on that one column. :) Stack is pretty useful, it might not be the most obvious cho...
How do I create a new branch?
...ow:
Right click on Trunk/ which you will be creating your Branch from:
Select Branch/Tag:
Type in location of your new branch, commit message, and any externals (if your repository has them):
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Python memoising/deferred lookup property decorator
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I found this method to be 7.6 times faster than the selected answer. (2.45 µs / 322 ns) See ipython notebook
– Dave Butler
Feb 28 '14 at 19:49
1
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Accessing outside variable using anonymous function as params
... same no matter what function is executing.
Code:
$result = '';
fetch("SELECT title FROM tbl", function($r) use (&$result) {
$result .= $r['title'];
});
But beware (taken from one of comments in previous link):
use() parameters are early binding - they use the variable's value at
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Registry Key '…' has value '1.7', but '1.6' is required. Java 1.7 is Installed and the Registry is P
...va Runtime Environment"- On right hand side you will get 4-5 rows . Please select "CurrentVersion" and right Click( select modify option) Change version to "1.7"
Now the magic has been completed
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How to clear MemoryCache?
...od
The workaround is:
List<string> cacheKeys = MemoryCache.Default.Select(kvp => kvp.Key).ToList();
foreach (string cacheKey in cacheKeys)
{
MemoryCache.Default.Remove(cacheKey);
}
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