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ERROR 1452: Cannot add or update a child row: a foreign key constraint fails
... table. Following query would be helpful to fetch those non-matching rows:
SELECT child_table.*
FROM child_table
LEFT JOIN parent_table
ON parent_table.referenced_column = child_table.referencing_column
WHERE parent_table.referenced_column IS NULL
Now, you can generally do one (or more) of th...
How do I determine k when using k-means clustering?
...core
range_n_clusters = [2, 3, 4] # clusters range you want to select
dataToFit = [[12,23],[112,46],[45,23]] # sample data
best_clusters = 0 # best cluster number which you will get
previous_silh_avg = 0.0
for n_clusters in range_n_clusters:
clusterer = KMeans...
How to scroll to specific item using jQuery?
... so:
$('html,body').animate({scrollTop: some_element.offset().top});
We select both html and body because the document scroller could be on either and it is hard to determine which. For modern browsers you can get away with $(document.body).
Or, to go to the top of the page:
$('html,body').anim...
How To Change DataType of a DataColumn in a DataTable?
...
Consider also altering the return type:
select cast(columnName as int) columnName from table
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What is default color for text in textview?
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This looks like it will properly select the colour based on theme, and will update for instance, if the app is in night mode.
– Brill Pappin
Aug 26 '15 at 15:47
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'System.Net.Http.HttpContent' does not contain a definition for 'ReadAsAsync' and no extension metho
...Api.Client in MyMVCProjectNameAndNotMyConsoleProjectName'. The next time I selected my Console project and typed the same thing in the package manager console. It said MyMVCProjectName already references Microsoft.AspNet.WebApi.Client. I am confused.
– Water Cooler v2
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Visual Studio debugger - Displaying integer values in Hex
...log.
Break after setting the variable.
Right mouse click the variable and select "Add Watch" or "QuickWatch"
Right mouse click the line in the Watch dialogue.
Uncheck "Hexadecimal Display"
The display will now be in decimal.
...
Sharing link on WhatsApp from mobile website (not application) for Android
... @HoldOffHunger yes it will open whatsapp application and the user have to select the contact to which he desires to share the link/content.
– ad08
Apr 4 '18 at 12:25
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Where is Xcode's build folder?
...ed
You can change the location of Target using:
Project editor -> select a target -> Build Settings -> Per-configuration Build Products Path
The default value is$(BUILD_DIR)/$(CONFIGURATION)$(EFFECTIVE_PLATFORM_NAME)
It makes sense if you want to create an autonomic Build locatio...
Java List.add() UnsupportedOperationException
...to other List implementations that are either immutable or only allow some selected changes.
You can find out about this by reading the documentation of UnsupportedOperationException and List.add(), which documents this to be an "(optional operation)". The precise meaning of this phrase is explaine...