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efficient way to implement paging
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LinqToSql will automatically convert a .Skip(N1).Take(N2) into the TSQL syntax for you. In fact, every "query" you do in Linq, is actually just creating a SQL query for you in the background. To test this, just run SQL Profiler while your application i...
Reorder levels of a factor without changing order of values
...sapply(dtf, class)
numbers letters
"integer" "factor"
Now, if you convert this factor to numeric, you'll get:
# return underlying numerical values
1> with(dtf, as.numeric(letters))
[1] 1 2 3 4
# change levels
1> levels(dtf$letters) <- letters[4:1]
1> dtf
numbers letters
1 ...
Javascript call() & apply() vs bind()?
...fined will be replaced with the global object and primitive values will be converted to objects. So if you don't use this in the function it doesn't matter.
– Amit Shah
May 18 '18 at 18:46
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Java logical operator short-circuiting
Which set is short-circuiting, and what exactly does it mean that the complex conditional expression is short-circuiting?
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Strings as Primary Keys in SQL Database [closed]
I am not very familiar with databases and the theories behind how they work. Is it any slower from a performance standpoint (inserting/updating/querying) to use Strings for Primary Keys than integers?
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What's the point of NSAssert, actually?
...Is that the reason why to use NSAssert? Or what else is the benefit of it? And is it right to put an NSAssert just above any assumption I make in code, like a function that should never receive a -1 as param but may a -0.9 or -1.1?
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Updating MySQL primary key
...delete u from user_interactions u, fixit
where fixit.user_2 = u.user_2
and fixit.user_1 = u.user_1
and fixit.type = u.type
and fixit.timestamp != u.timestamp;
alter table user_interactions add primary key (user_2, user_1, type );
unlock tables;
The lock should stop further updates comi...
Dealing with commas in a CSV file
I am looking for suggestions on how to handle a csv file that is being created, then uploaded by our customers, and that may have a comma in a value, like a company name.
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Why charset names are not constants?
Charset issues are confusing and complicated by themselves, but on top of that you have to remember exact names of your charsets. Is it "utf8" ? Or "utf-8" ? Or maybe "UTF-8" ? When searching internet for code samples you will see all of the above. Why not just make them named constants and use ...
In Ruby how do I generate a long string of repeated text?
...ts. It certainly could (for example, automatically making a best-effort to convert the argument to a FixNum) but the language designers decided against embracing Ruby's Perlish inspirations too fully.
– FMc
Jan 15 '17 at 2:12
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