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Pandas every nth row
...] # Excludes every 3rd row starting from 0
df2 = df[df.index % 3 == 0] # Selects every 3rd raw starting from 0
This arithmetic based sampling has the ability to enable even more complex row-selections.
This assumes, of course, that you have an index column of ordered, consecutive, integers star...
Recommended way of making React component/div draggable
...ground is important for performance */
background: white;
/* avoid selecting text while dragging */
user-select: none;
}
Example on JSFiddle.
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SVN command to delete all locally missing files
...TortoiseSVN, just do a Check for Modifications, sort by the Status column, select all the entries marked missing, right-click to open the context menu, and select Delete. Finally, commit to publish the changes to the repository.
If you are on Windows, but prefer the command-line and enjoy dabbling ...
Using Excel OleDb to get sheet names IN SHEET ORDER
...nzip
ZipArchive archive = new ZipArchive(data);
//select the correct file from the archive
ZipArchiveEntry appxmlFile = archive.Entries.SingleOrDefault(e => e.FullName == "docProps/app.xml");
//read the xml
XDocument xdoc = XDocument.L...
What is a unix command for deleting the first N characters of a line?
...
Use cut. Eg. to strip the first 4 characters of each line (i.e. start on the 5th char):
tail -f logfile | grep org.springframework | cut -c 5-
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ALTER TABLE to add a composite primary key
...dexed from left to right.
For example, consider the following queries:
A) SELECT person, place, thing FROM provider WHERE person = 'foo' AND thing = 'bar';
B) SELECT person, place, thing FROM provider WHERE person = 'foo' AND place = 'baz';
C) SELECT person, place, thing FROM provider WHERE person ...
Doctrine - How to print out the real sql, not just the prepared statement?
...hoWriteSQLWithoutParamsLogger implements SQLLogger
{
const QUERY_TYPE_SELECT="SELECT";
const QUERY_TYPE_UPDATE="UPDATE";
const QUERY_TYPE_INSERT="INSERT";
const QUERY_TYPE_DELETE="DELETE";
const QUERY_TYPE_CREATE="CREATE";
const QUERY_TYPE_ALTER="ALTER";
private $dbPlat...
Why isn't vector a STL container?
...l directly. Workarounds to
avoid this range from using a different type (char, unsigned char) or
container (like deque) to use wrapper types or further specialize for
specific allocator types.
bitset is a class that provides a similar functionality for fixed-size
arrays of bits.
...
What is __init__.py for?
...ll fail.
The __init__.py file is usually empty, but can be used to export selected portions of the package under more convenient name, hold convenience functions, etc.
Given the example above, the contents of the init module can be accessed as
import spam
based on this
...
Why does flowing off the end of a non-void function without returning a value not produce a compiler
...times it is wrong and you have to put in an unnecessary return statement.
char getChoice() {
int ch = read();
if (ch == -1 || ch == 'q') {
System.exit(0);
}
else {
return (char) ch;
}
// Cannot reach here, but still an error.
}
It's a philosophical differ...