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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...
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...
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...
Case insensitive string compare in LINQ-to-SQL
... Well, if you have a case sensitive database, and you store in mixed case and search in Upper case, you won't get matches. If you upcase both the data and the query in your search, then you're converting all the text you're searching over for every query, which isn't performant.
...
How to insert element into arrays at specific position?
...whole problem is solved with the array_splice function. For associative or mixed arrays, you probably don't want numeric keys to be re-indexed so using + is entirely appropriate.
– meustrus
Jan 15 '15 at 18:36
...
Why is an MD5 hash created by Python different from one created using echo and md5sum in the shell?
...k that is typically thought as better done in shell scripts. The nature of mixed data and code, and a different syntax for each command all make shell scripts invisibly error prone
– jsbueno
Apr 17 '11 at 17:05
...
Proper use cases for Android UserManager.isUserAGoat()?
...ing produces a warning in Java (that can further produce compile errors if mixed with return statements, leading to unreachable code):
while (1 == 2) { // Note that "if" is treated differently
System.out.println("Unreachable code");
}
However this is legal:
while (isUserAGoat()) {
System...