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C++ equivalent of java's instanceof
...>doSomething();
}
This requires your compiler to have rtti support enabled.
EDIT:
I've had some good comments on this answer!
Every time you need to use a dynamic_cast (or instanceof) you'd better ask yourself whether it's a necessary thing. It's generally a sign of poor design.
Typical wor...
count the frequency that a value occurs in a dataframe column
...
Use groupby and count:
In [37]:
df = pd.DataFrame({'a':list('abssbab')})
df.groupby('a').count()
Out[37]:
a
a
a 2
b 3
s 2
[3 rows x 1 columns]
See the online docs: http://pandas.pydata.org/pandas-docs/stable/groupby.htm...
How can Perl's print add a newline by default?
...lso use say in Perl 5.10 or 5.12 if you add
use feature qw(say);
to the beginning of your program. Or you can use Modern::Perl to get this and other features.
See perldoc feature for more details.
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How do I get current date/time on the Windows command line in a suitable format for usage in a file/
...t it's 2016 I'd use PowerShell for this unless there's a really compelling backwards-compatible reason for it, particularly because of the regional settings issue with using date . See @npocmaka's https://stackoverflow.com/a/19799236/8479
...
Realistic usage of the C99 'restrict' keyword?
I was browsing through some documentation and questions/answers and saw it mentioned. I read a brief description, stating that it would be basically a promise from the programmer that the pointer won't be used to point somewhere else.
...
Best way to select random rows PostgreSQL
...ditional info in the comments),
You have a numeric ID column (integer numbers) with only few (or moderately few) gaps.
Obviously no or few write operations.
Your ID column has to be indexed! A primary key serves nicely.
The query below does not need a sequential scan of the big table, only an in...
Generating random integer from a range
...a function which would generate a random integer in given range (including border values). I don't unreasonable quality/randomness requirements, I have four requirements:
...
How can I reverse the order of lines in a file?
...
BSD tail:
tail -r myfile.txt
Reference: FreeBSD, NetBSD, OpenBSD and OS X manual pages.
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How do I prompt for Yes/No/Cancel input in a Linux shell script?
..., No , or Cancel type question.
How do I accomplish this in a typical bash prompt?
31 Answers
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How to encode URL parameters?
...om/?username=unknown&password=unknown";
var encodedURL= "http://www.foobar.com/foo?imageurl=" + encodeURIComponent(myUrl);
DEMO: http://jsfiddle.net/Lpv53/
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