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Which parts of Real World Haskell are now obsolete or considered bad practice?
...move return from Monad, so the Monad instance in Real World Haskell will really be out of sync with the real world.
That being said, it's still a useful resource for general guidelines. But keep in mind that many libraries changed since its release.
Something you can read along while reading RWH i...
What is the use case of noop [:] in bash?
... to do.
while keep_waiting; do
: # busy-wait
done
The : builtin dates all the way back to the Thompson shell, it was present in Unix v6. : was a label indicator for the Thompson shell's goto statement. The label could be any text, so : doubled up as a comment indicator (if there is no goto comm...
Way to read first few lines for pandas dataframe
...d of time? I have a large file that takes a long time to read, and occasionally only want to use the first, say, 20 lines to get a sample of it (and prefer not to load the full thing and take the head of it).
...
Finding differences between elements of a list
...
Actually simply list(map(operator.sub, t[1:], t[:-1])) will do.
– blhsing
Aug 6 '18 at 15:24
add a comme...
LINQ .Any VS .Exists - What's the difference?
...
I later made a post in another thread where I listed all the Linq "equivalents" of the .NET 2 List<> instance methods.
– Jeppe Stig Nielsen
Dec 1 '15 at 8:44
...
What is the difference between float and double?
...i.e. using one or the other does not seem to affect the results. Is this really the case? When are floats and doubles interchangeable? What are the differences between them?
...
JPA: How to have one-to-many relation of the same Entity type
...em.persist(daughter);
em.getTransaction().commit();
}
In this case, all three entity instances must be persisted before transaction commit. If I fail to persist one of the entities in the graph of parent-child relationships, then an exception is thrown on commit(). On Eclipselink, this is a...
How to duplicate virtualenv
...is to use pip to generate a requirements file. A requirements file is basically a file that contains a list of all the python packages you want to install (or have already installed in case of file generated by pip), and what versions they're at.
To generate a requirements file, go into your origin...
Convert pandas dataframe to NumPy array
...p.nan)
# array([ 1., 2., nan])
This is called out in the docs.
If you need the dtypes...
As shown in another answer, DataFrame.to_records is a good way to do this.
df.to_records()
# rec.array([('a', -1, 4), ('b', 2, 5), ('c', 3, 6)],
# dtype=[('index',...
Download a file with Android, and showing the progress in a ProgressDialog
...Use AsyncTask and show the download progress in a dialog
This method will allow you to execute some background processes and update the UI at the same time (in this case, we'll update a progress bar).
Imports:
import android.os.PowerManager;
import java.io.InputStream;
import java.io.OutputStream...