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How to copy an object in Objective-C
...lways with reference types, there are two notions of "copy". I'm sure you know them, but for completeness.
A bitwise copy. In this, we just copy the memory bit for bit - this is what NSCopyObject does. Nearly always, it's not what you want. Objects have internal state, other objects, etc, and ofte...
SQL query to find record with ID not in another table
... 20 datas, It works, but when i have 20000 datas, it not work, Iam confuse now.
– Frank
Nov 2 '16 at 3:25
1
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Covariance, Invariance and Contravariance explained in plain English?
...must be supertype of U (contravariant, as contra inheritance direction).
Now co- and contra- relate to B being subtype of A. The following stronger typings may be introduced with more specific knowledge. In the subtype.
Covariance (available in Java) is useful, to say that one returns a more spec...
What is the difference between Digest and Basic Authentication?
...http response code 200 ok ,i.e, the username:password were correct .
Now , In the Authorization header it shows that it is Basic Authorization followed by some random string .This String is the encoded (Base64) version of the credentials admin:aadd (including colon ) .
2 . Http Digest Authent...
Why Choose Struct Over Class?
...ruct version took 0.010532942s (900 times faster)
OLD RESULTS (from unknown time)
(Ran on struct/class with 1 field, not 10)
With release build on my MacBook Pro:
The class version took 1.10082 sec
The struct version took 0.02324 sec (50 times faster)
...
What column type/length should I use for storing a Bcrypt hashed password in a Database?
...define the column as CHAR(60) CHARACTER SET latin1 COLLATE latin1_bin, you now get the advantages of accurate string comparison without needing a binary column.
– Ben
Feb 25 '14 at 16:01
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Git Cherry-pick vs Merge Workflow
...erge it into 'maint' and into 'master'... though in this case you need to know that said bugfix applies to both branches.
– Jakub Narębski
Oct 29 '11 at 11:41
4
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How does LMAX's disruptor pattern work?
... entry, and stores the result in field a in the entry. A then move on, and now B can read the entry, and the value of a A stored. If reader C does not depend on A, C should not attempt to read a.
This is indeed an interesting programming model. Regardless of the performance, the model alone can ben...
Parallel.ForEach vs Task.Factory.StartNew
...heduler, by default, uses the new ThreadPool, which handles this very well now.
– Reed Copsey
Feb 17 '11 at 16:42
Than...
Read an Excel file directly from a R script
...
And now there is readxl:
The readxl package makes it easy to get data out of Excel and into R.
Compared to the existing packages (e.g. gdata, xlsx, xlsReadWrite etc)
readxl has no external dependencies so it's easy to ins...