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How can I handle R CMD check “no visible binding for global variable” notes when my ggplot2 syntax i
... it would be best to ignore them, but my code uses lots of ggplot and data.table, and thus has tons of these warnings, which have kept me from noticing other more important warnings that really were problems I needed to fix.
– Ken Williams
Nov 25 '13 at 20:06
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Best data type for storing currency values in a MySQL database
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My benefit was this.. I needed all my table rows to equal a particular amount of money. Let's say that amount is $10.00. As new rows get added each row amount changes. If there are 3 rows in the table. 10 / 3 = 3.3333333333... but with only 2 decimals they are st...
List of Big-O for PHP functions
...all: Thanks! I did a bit of reading and it turns out PHP uses 'nested' hashtables for collisions. That is, instead of a logn structure for collisions it simply uses another hashtable. And I do understand that practically speaking PHP hashtables give O(1) performance, or at least O(1) on average - t...
When should I use semicolons in SQL Server?
... you must use the semicolon. The first situation is where you use a Common Table Expression (CTE), and the CTE is not the first statement in the batch. The second is where you issue a Service Broker statement and the Service Broker statement is not the first statement in the batch.
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C++ performance challenge: integer to std::string conversion
... first one is a fun implementation that doesn't use any precomputed lookup tables or explicit division/modulo. This one is competitive with the others with gcc and with all but Timo's on msvc (for a good reason that I explain below). The second algorithm is my actual submission for highest performan...
What does “static” mean in C?
...If we compile:
int i = 0;
static int si = 0;
and disassemble the symbol table with:
readelf -s main.o
the output contains:
Num: Value Size Type Bind Vis Ndx Name
5: 0000000000000004 4 OBJECT LOCAL DEFAULT 4 si
10: 0000000000000000 4 OBJECT GLOBAL DEFAULT...
Use a LIKE statement on SQL Server XML Datatype
If you have a varchar field you can easily do SELECT * FROM TABLE WHERE ColumnA LIKE '%Test%' to see if that column contains a certain string.
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How to check if a value exists in an array in Ruby
...rnally, you need to use a different data structure, such as a perfect hash table with fixed sized keys. Given that there's no way to test for membership in an array without looping internally, I interpreted the question to mean "without having to write the loop explicitly myself"
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What's the false operator in C# good for?
...er that nullity could be checked explicitly.
Comparing to SQL, imagine a table Table with 3 rows with value Foo set to true, 3 rows with value Foo set to false and 3 rows with value Foo set to null.
SELECT COUNT(*) FROM Table WHERE Foo = TRUE OR Foo = FALSE
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In order to count all rows you'd ha...
Why doesn't Objective-C support private methods?
... were private; i.e. this could be achieved by adding a private-only method table to the Class structure.
There would be no way for a private
method to short-circuit this check or
skip the runtime?
It couldn't skip the runtime, but the runtime wouldn't necessarily have to do any...