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What's the right way to pass form element state to sibling/parent elements?
...ContextContainer = React.createContext(null);
const initialAppState = {
selected: "Nothing"
};
function App() {
// The app has a state variable and update handler
const [appState, updateAppState] = useState(initialAppState);
return (
<div>
<h1>Passing state between c...
MySQL: Sort GROUP_CONCAT values
... see http://dev.mysql.com/doc/refman/...tions.html#function_group-concat:
SELECT student_name,
GROUP_CONCAT(DISTINCT test_score ORDER BY test_score DESC SEPARATOR ' ')
FROM student
GROUP BY student_name;
share
...
Efficient paging in SQLite with millions of records
...red field(s), and continue just after them when displaying the next page:
SELECT *
FROM MyTable
WHERE SomeColumn > LastValue
ORDER BY SomeColumn
LIMIT 100;
(This is explained with more detail on the SQLite wiki.)
When you have multiple sort columns (and SQLite 3.15 or later), you can use a ro...
Finding ALL duplicate rows, including “elements with smaller subscripts”
...gt;% filter(n > 1) # data frame
df %>% add_count(col1, col2) %>% select(n) > 1 # logical vector
For duplicate rows (considering all columns):
df %>% group_by_all %>% add_tally %>% ungroup %>% filter(n > 1)
df %>% group_by_all %>% add_tally %>% ungroup %>% ...
How to change the background color of a UIButton while it's highlighted?
...ged" forState:UIControlStateHighlighted];
[myButton addTarget:self action:@selector(buttonHighlight:) forControlEvents:UIControlEventTouchDown];
[myButton addTarget:self action:@selector(buttonNormal:) forControlEvents:UIControlEventTouchUpInside];
Option 2:
Return an image made from the highligh...
XDocument or XmlDocument
...er>
XElement customersElement = new XElement("customers",
customers.Select(c => new XElement("customer",
new XAttribute("name", c.Name),
new XAttribute("lastSeen", c.LastOrder)
new XElement("address",
new XAttribute("town", c.Town),
new XAttr...
Node.js Best Practice Exception Handling
...any different sources on this topic including code example and quotes from selected blog posts. The complete list of best practices can be found here
Best practices of Node.JS error handling
Number1: Use promises for async error handling
TL;DR: Handling async errors in callback style is proba...
Xcode Command /usr/bin/codesign failed with exit code 1 : errSecInternalComponent
...
Open Keychain Access, then in the File menu select Lock All Keychains.
Then go back to Xcode and clean and rebuild. It will prompt you for your password again to unlock the keychain.
After this, assuming you have no other compile issues, it will succeed!
...
Indent multiple lines quickly in vi
...n a row, such as fixing some tags pasted in to an XML file. Rather than re-select the block in visual mode each time, one can use 'gv' to reuse the last visual block. Reference superuser.com/questions/220666/…
– David Mann
May 9 '14 at 3:37
...
How to use DbContext.Database.SqlQuery(sql, params) with stored procedure? EF Code First C
...t accepted as the answer, its a much easier to write solution than the one selected as answer.
– Nikkoli
Oct 2 '12 at 18:43
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