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An example of how to use getopts in bash
...pecify strength, either 45 or 90.
h | *) # Display help.
$ ./foo.sh -s 123 -p any_string
Strength needs to be either 45 or 90, 123 found instead.
p is any_string
$ ./foo.sh -s 90 -p any_string
Strength is 90.
p is any_string
See: Small getopts tutorial at Bash Hackers Wiki
...
Ruby, remove last N characters from a string?
...diomatic (and I'd argue, even more readable than other answers here):
'abc123'.delete_suffix('123') # => "abc"
'abc123'.delete_suffix!('123') # => "abc"
It's even significantly faster (almost 40% with the bang method) than the top answer. Here's the result of the same benchmark:
...
How can I convert a string to a number in Perl?
...
This is a simple solution:
Example 1
my $var1 = "123abc";
print $var1 + 0;
Result
123
Example 2
my $var2 = "abc123";
print $var2 + 0;
Result
0
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Removing all non-numeric characters from string in Python
... this is the most efficient way, but:
>>> ''.join(c for c in "abc123def456" if c.isdigit())
'123456'
The ''.join part means to combine all the resulting characters together without any characters in between. Then the rest of it is a list comprehension, where (as you can probably guess) ...
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
*********
...
Passing data between a fragment and its container activity
...
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...
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 {
...
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 to get the data-id attribute?
...
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- ...