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When to use generic methods and when to use wild-card?
... c.add(o); // correct
}
}
But the following will result in compile time error.
static <T> void fromArrayToCollection(T[] a, Collection<?> c) {
for (T o : a) {
c.add(o); // compile time error
}
}
Postgres: clear entire database before re-creating / re-populating from bash script
...
one trick that saves me time is $ sudo -u postgres dropdb DATABASE_NAME
– Alvin
Jan 6 '14 at 23:31
37
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An example of how to use getopts in bash
...urce ./getopt.sh
USAGE="-u USER -d DATABASE -p PASS -s SID [ -a START_DATE_TIME ]"
parse_options "${USAGE}" ${@}
echo ${USER}
echo ${START_DATE_TIME}
Old answer:
I recently needed to use a generic approach. I came across with this solution:
#!/bin/bash
# Option Description:
# ------------------...
while (1) Vs. for (;;) Is there a speed difference?
... but chances are the code inside of the loop is going to be a few thousand times more expensive than the loop itself anyway, so who cares?
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How to count number of files in each directory?
...older
sort to sort the list of foldernames
uniq -c to return the number of times each foldername has been counted
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Is there still any reason to learn AWK?
...s that would otherwise take a dozen lines to code. I cannot count how many times I have used the form: awk '{print $1, $2}'
– galaxywatcher
Jan 9 '10 at 9:21
2
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Numpy: find first index of value fast
... the array); last value is a needle that's not in the array. Y-axis is the time to find it.
The array had 1 million elements and tests were run 100 times. Results still fluctuate a bit, but the qualitative trend is clear: Python and f2py quit at the first element so they scale differently. Python...
How to make an unaware datetime timezone aware in python
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In general, to make a naive datetime timezone-aware, use the localize method:
import datetime
import pytz
unaware = datetime.datetime(2011, 8, 15, 8, 15, 12, 0)
aware = datetime.datetime(2011, 8, 15, 8, 15, 12, 0, pytz.UTC)
now_aware = pytz.utc.localize(...
A std::map that keep track of the order of insertion?
... = 0;
insertOrder.push_back("baz");
/* Increment things in myTable 100000 times */
// Print the final results.
for (int i = 0; i < insertOrder.size(); ++i)
{
const std::string &s = insertOrder[i];
std::cout << s << ' ' << myTable[s] << '\n';
}
...
Storing Image Data for offline web application (client-side storage database)
...l files!
Results
Chrome: Fetch (6.551s), Store (8.247s), Total Elapsed Time: (13.714s)
FireFox: Fetch (0.422s), Store (31.519s), Total Elapsed Time: (32.836s)
IE 10: Fetch (0.668s), Store: (0.896s), Total Elapsed Time: (3.758s)
...