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What underlies this JavaScript idiom: var self = this?
...his even as the context is changing. It's a technique often used in event handlers (especially in closures).
Edit: Note that using self is now discouraged as window.self exists and has the potential to cause errors if you are not careful.
What you call the variable doesn't particularly matter. va...
invalid byte sequence for encoding “UTF8”
...k the encoding of your database in pgAdmin. Just right-click the database, and select "Properties".
But that error seems to be telling you there's some invalid UTF8 data in your source file. That means that the copy utility has detected or guessed that you're feeding it a UTF8 file.
If you're runn...
The input is not a valid Base-64 string as it contains a non-base 64 character
I have a REST service that reads a file and sends it to another console application after converting it to Byte array and then to Base64 string. This part works, but when the same stream is received at the application, it gets manipulated and is no longer a valid Base64 string. Some junk characters ...
How can I check if a var is a string in JavaScript?
...Also, you may as well use == (equality comparison operator) since both operands are Strings (typeof always returns a String), JavaScript is defined to perform the same steps had I used === (strict comparison operator).
As Box9 mentions, this won't detect a instantiated String object.
You can dete...
Swift - encode URL
...lowed)
print(escapedString!)
Output:
test%2Ftest
Swift 1
In iOS 7 and above there is stringByAddingPercentEncodingWithAllowedCharacters
var originalString = "test/test"
var escapedString = originalString.stringByAddingPercentEncodingWithAllowedCharacters(.URLHostAllowedCharacterSet())
prin...
How to list the tables in a SQLite database file that was opened with ATTACH?
What SQL can be used to list the tables, and the rows within those tables in an SQLite database file - once I have attached it with the ATTACH command on the SQLite 3 command line tool?
...
UITableViewCell subview disappears when cell is selected
...can Solve this problem by overriding Tableview cell's setSelected:animated and setHighlighted:animated and resetting view background color.
In Objective C :
- (void)setSelected:(BOOL)selected animated:(BOOL)animated {
UIColor *color = self.yourView.backgroundColor;
[super setSelected...
How to rollback a specific migration?
...STEP=5
Will also rollback all the migration that happened later (4, 3, 2 and also 1).
To roll back all migrations back to (and including) a target migration, use: (This corrected command was added AFTER all the comments pointing out the error in the original post)
rake db:migrate VERSION=2010090...
Introducing FOREIGN KEY constraint may cause cycles or multiple cascade paths - why?
I've been wrestling with this for a while and can't quite figure out what's happening. I have a Card entity which contains Sides (usually 2) - and both Cards and Sides have a Stage. I'm using EF Codefirst migrations and the migrations are failing with this error:
...
sed or awk: delete n lines following a pattern
How would I mix patterns and numeric ranges in sed (or any similar tool - awk for example)? What I want to do is match certain lines in a file, and delete the next n lines before proceeding, and I want to do that as part of a pipeline.
...