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Apply a function to every row of a matrix or a data frame
Suppose I have a n by 2 matrix and a function that takes a 2-vector as one of its arguments. I would like to apply the function to each row of the matrix and get a n-vector. How to do this in R?
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Test whether string is a valid integer
...of "+" (e.g. +30) which obviously is an integer.
Results:
$ int_check.sh 123
123 is an integer !!
$ int_check.sh 123+
ERROR: first parameter must be an integer.
$ int_check.sh -123
-123 is an integer !!
$ int_check.sh +30
+30 is an integer !!
$ int_check.sh -123c
ERROR: first parameter must be...
How can I pad a String in Java?
...*chars
Display '*' for characters of password:
String password = "secret123";
String padded = String.format("%"+password.length()+"s", "").replace(' ', '*');
output has the same length as the password string:
secret123
*********
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Passing data between a fragment and its container activity
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Since you are accessing a function within YOUR Activity (and not the parent Android activity) you will need to cast your getActivity() call: ((MyActivity) getActivity()).getResult();
– Nick
Feb 21 '12 at 17...
How to get the data-id attribute?
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To get the contents of the attribute data-id (like in <a data-id="123">link</a>) you have to use
$(this).attr("data-id") // will return the string "123"
or .data() (if you use newer jQuery >= 1.4.3)
$(this).data("id") // will return the number 123
and the part after data- ...
Android - implementing startForeground for a service?
...recent versions of Android. This is how i solved it:
Activity:
override fun onCreate(savedInstanceState: Bundle?) {
val intent = Intent(this, BackgroundService::class.java)
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
startForegroundService(intent)
} else {
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Host 'xxx.xx.xxx.xxx' is not allowed to connect to this MySQL server
...ccess the MySQL Database on your actual server (say your remote address is 123.123.123.123 at port 3306 as user 'root' and I want to change permissions on database 'dataentry'. Remember to change the IP Address, Port, and database name to your settings)
mysql -u root -p
Enter password: <enter p...
How to use the 'sweep' function
When I look at the source of R Packages, i see the function sweep used quite often.
Sometimes it's used when a simpler function would have sufficed (e.g., apply ),
other times, it's impossible to know exactly what it's is doing without
spending a fair amount of time to step through the code block...
How do I format a string using a dictionary in python-3.x?
...yntax, available since Python 3.6:
>>> geopoint = {'latitude':41.123,'longitude':71.091}
>>> print(f'{geopoint["latitude"]} {geopoint["longitude"]}')
41.123 71.091
Note the outer single quotes and inner double quotes (you could also do it the other way around).
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How to get the client IP address in PHP [duplicate]
...answered Oct 8 '14 at 16:20
josh123a123josh123a123
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