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How can I output leading zeros in Ruby?
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If the maximum number of digits in the counter is known (e.g., n = 3 for counters 1..876), you can do
str = "file_" + i.to_s.rjust(n, "0")
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How important is the order of columns in indexes?
...while Column 1 above does negate 1/2 the possibilities, the index already knows which index page to go straight to for the Column2 value, it does not necessary need Column 1 to narrow down the set.
– CodeCowboyOrg
Mar 23 '15 at 17:57
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Jackson Vs. Gson [closed]
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Gson 1.6 now includes a low-level streaming API and a new parser which is actually faster than Jackson.
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Best way to split string into lines
...ion<Action> measure = (Action func) => {
var start = DateTime.Now;
for (int i = 0; i < 100000; i++) {
func();
}
var duration = DateTime.Now - start;
Console.WriteLine(duration);
};
var input = "";
for (int i = 0; i < 100; i++)
{
input += "1 \r2\r\n3\n4...
Using -performSelector: vs. just calling the method
... performSelector is also useful to suppress compile warnings. If you know the method exists (like after using respondsToSelector), it will stop Xcode from saying "may not respond to your_selector". Just don't use it instead of finding out the real cause of the warning. ;)
–...
How can I tell when a MySQL table was last updated?
...ENT_TIMESTAMP,
KEY (updated_at)
);
mysql> INSERT INTO foo VALUES (1, NOW() - INTERVAL 3 DAY), (2, NOW());
mysql> SELECT * FROM foo;
+----+------+---------------------+
| id | x | updated_at |
+----+------+---------------------+
| 1 | NULL | 2013-08-18 03:26:28 |
| 2 | NULL | ...
data.frame rows to a list
...mp;
}
res.attr("names") = x.attr("row.names");
return res;
}
Now caompare with purrr:
benchmark(
purrr = by_row(x, function(v) list(v)[[1L]], .collate = "list")$.out,
rcpp = df2list(x)
)
Results:
Benchmark summary:
Time units : milliseconds
expr n.eval min lw.qu median m...
How do you convert a DataTable into a generic list?
...(DateTime )); for(int i=0;i<=1000;i++){dt.Rows.Add(i, "foo", DateTime.Now);}
– Rahul Garg
Jul 25 '18 at 10:56
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Why are preprocessor macros evil and what are the alternatives?
...gers, you can't "see" what the macro translates to. So you don't actually know what is going on.
Replacement: Use enum or const T
For "function-like" macros, because the debugger works on a "per source line where you are" level, your macro will act like a single statement, no matter if it's one ...
Detect backspace in empty UITextField
...essed in the iPhone keyboard on a UITextField that is empty? I want to know when Backspace is pressed only if the UITextField is empty.
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