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Group by multiple columns in dplyr, using string vector input
...ike s_group_by, s_mutate, s_filter, etc that use string arguments. You can mix them with the normal dplyr functions. For example
cols = c("cyl","gear")
mtcars %.%
s_group_by(cols) %.%
s_summarise("avdisp=mean(disp), max(disp)") %.%
arrange(avdisp)
...
Multi-line string with extra space (preserved indentation)
...ree\n"
printf "%b" "$text" > filename
Another solution is achieved by mixing printf and sed.
if something
then
printf '%s' '
this is line one
this is line two
this is line three
' | sed '1d;$d;s/^ //g'
fi
It is not easy to refactor code formatted like this as you hard...
How to handle ListView click in Android
... public void onItemClick(AdapterView<?> parent, View view, int position, long id) { Toast.makeText(MainActivity.this, "You Clicked at " +countries[+ position], Toast.LENGTH_SHORT).show(); }
– bourax webmaster
Apr 5 '14 at 9:51
...
What's the difference between a mock & stub?
...ur SUT handles receiving messages, mocks test how your SUT sends messages. Mixing up the 2 is likely to lead to bad OO design.
– dave1010
Aug 24 '15 at 7:41
8
...
What does the 'b' character do in front of a string literal?
....
>>> b'\xE2\x82\xAC'.decode('UTF-8')
'€'
But you can't freely mix the two types.
>>> b'\xEF\xBB\xBF' + 'Text with a UTF-8 BOM'
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: can't concat bytes to str
The b'...' notation is somew...
Entity Framework: table without primary key
...
@MahmoudMoravej: First off, don't mix up the ideas of clustering indexes and primary keys. They aren't the same thing. You can have very highly performant inserts on tables with clustered indicies on IDENTITY columns. If you run into issues with index main...
Is there a way to check if a file is in use?
...
Updated NOTE on this solution: Checking with FileAccess.ReadWrite will fail for Read-Only files so the solution has been modified to check with FileAccess.Read. While this solution works because trying to check with FileAccess.Read will fail if the fi...
Disable a Button
I want to disable a button ( UIButton ) on iOS after it is clicked. I am new to developing for iOS but I think the equivalent code on objective - C is this:
...
Max length UITextField
...
With Swift 5 and iOS 12, try the following implementation of textField(_:shouldChangeCharactersIn:replacementString:) method that is part of the UITextFieldDelegate protocol:
func textField(_ textField: UITextField, shouldChangeCharactersIn ...
XML Schema: Element with attributes containing only text?
...t works for me:
<xsd:element name="option">
<xsd:complexType mixed="true">
<xsd:attribute name="value" use="optional" type="xsd:string"/>
</xsd:complexType>
</xsd:element>
shar...