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Reshape three column data frame to matrix (“long” to “wide” format) [duplicate]
...' the matrix.
#'
#' @param data data.frame: input data
#' @param rowtitle string: row-dimension; name of the column in data, which distinct values should be used as row names in the output matrix
#' @param coltitle string: col-dimension; name of the column in data, which distinct values should be u...
What programming practice that you once liked have you since changed your mind about? [closed]
...ian notation (both Forms and Systems).
I used to prefix everything. strSomeString or txtFoo.
Now I use someString and textBoxFoo. It's far more readable and easier for someone new to come along and pick up. As an added bonus, it's trivial to keep it consistant -- camelCase the control and append a u...
Is it possible for a computer to “learn” a regular expression by user-provided examples?
...
Yes, it's certainly "possible"; Here's the pseudo-code:
string MakeRegexFromExamples(<listOfPosExamples>, <listOfNegExamples>)
{
if HasIntersection(<listOfPosExamples>, <listOfNegExamples>)
return <IntersectionError>
string regex = "";
...
Echo a blank (empty) line to the console from a Windows batch file [duplicate]
... @MatteoItalia, It's nothing to do with speed. If it's doing something extra (search first for a file named echo without extension) then it's wrong and if there's a file as such, it'll indeed fail. Extra points if the batchjob fails on a weekend while everyone is partying hard half-a-country awa...
Difference between single and double square brackets in Bash
...nsion.
expr a \< b > /dev/null: POSIX equivalent², see: How to test strings for lexicographic less than or equal in Bash?
&& and ||
[[ a = a && b = b ]]: true, logical and
[ a = a && b = b ]: syntax error, && parsed as an AND command separator cmd1 &&...
How do I show the number keyboard on an EditText in android?
...found this implementation useful, shows a better keyboard and limits input chars.
<EditText
android:inputType="phone"
android:digits="1234567890"
...
/>
Additionally, you could use android:maxLength to limit the max amount of numbers.
To do this programmatically:
editText.set...
Collections.emptyMap() vs new HashMap()
...e this, and does not allow null references:
public ResultSet executeQuery(String query, Map<String, Object> queryParameters);
If you have a query that doesn't take any parameters, it's certainly a bit wasteful to create a HashMap, which involves allocating an array, when you could just pass...
The easiest way to transform collection to array?
...of the correct type. And in this case, honestly, I wouldn't care about one extra single empty array in my application. That's far below noise level.
– Andreas Dolk
Jul 21 '10 at 6:28
...
Deleting all files in a directory with Python
... list of file names which end it '.bak'. The elements of the list are just strings.
Then you could use os.unlink to remove the files. (PS. os.unlink and os.remove are synonyms for the same function.)
#!/usr/bin/env python
import glob
import os
directory='/path/to/dir'
os.chdir(directory)
files=glo...
getSupportActionBar from inside of Fragment ActionBarCompat
...).
((AppCompatActivity)getActivity()).getSupportActionBar().setSubtitle(R.string.subtitle);
You do need the cast. It's not poor design, it's backwards compatibility.
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