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Apply multiple functions to multiple groupby columns
... group. When aggregating, g will be a Series. Passing g.index to df.ix[] selects the current group from df. I then test if column C is less than 0.5. The returned boolean series is passed to g[] which selects only those rows meeting the criteria.
In [95]: cust = lambda g: g[df.loc[g.index]['C']...
What should every developer know about databases? [closed]
...fluence that choice;
The concept of coverage (why you shouldn't just write SELECT *);
The difference between a clustered and non-clustered index;
Why more/bigger indexes are not necessarily better;
Why you should try to avoid wrapping filter columns in functions.
Designers should also be aware of ...
How to fetch FetchType.LAZY associations with JPA and Hibernate in a Spring Controller
... PersonRepository extends JpaRepository<Person, Long> {
@Query("SELECT p FROM Person p JOIN FETCH p.roles WHERE p.id = (:id)")
public Person findByIdAndFetchRolesEagerly(@Param("id") Long id);
}
This method will use JPQL's fetch join clause to eagerly load the roles association in a...
Pretty printing XML with javascript
...tch="node()|@*">
<xsl:copy>
<xsl:apply-templates select="node()|@*"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
When applying this transformation on the provided XML document:
<root><node/></root>
most XSLT processo...
Is there a way of making strings file-path safe in c#?
...id chars and an _ for invalid ones
var validFilename = new string(filename.Select(ch => invalidFileNameChars.Contains(ch) ? '_' : ch).ToArray());
To replace invalid characters (and avoid potential name conflict like Hell* vs Hell$):
static readonly IList<char> invalidFileNameChars = Path...
RichTextBox (WPF) does not have string property “Text”
...
How about just doing the following:
_richTextBox.SelectAll();
string myText = _richTextBox.Selection.Text;
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Is there a query language for JSON?
...joined items
.equals("location.state", "TX")
//and even do custom selections
.select(function(rec) {
return {
fullname : rec.firstname + " " + rec.lastname,
city : rec.location.city,
ageInTenYears : (rec.age + 10)
};
});
It's ful...
How to remove unused imports from Eclipse
...rences → Java → Editor → Save Actions.
Check the option "Perform the selected actions on save".
Check the option "Organize imports".
Now every time you save your classes, eclipse will take care of removing the unused imports.
...
Making the Android emulator run faster
...ve to properly shut down your emulator device (hold the power button, then select Power off) to avoid having errors when you start it the next time (I could just close the ARM emulator, but with the Intel emulator, just closing seems to create problems).
– ADTC
...
MySQL: Invalid use of group function
..., not WHERE.
The difference is: the WHERE clause filters which rows MySQL selects. Then MySQL groups the rows together and aggregates the numbers for your COUNT function.
HAVING is like WHERE, only it happens after the COUNT value has been computed, so it'll work as you expect. Rewrite your subque...