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MySQL stored procedure vs function, which would I use when?
...TE FUNCTION hello (s CHAR(20))
RETURNS CHAR(50) DETERMINISTIC
RETURN CONCAT('Hello, ',s,'!');
Query OK, 0 rows affected (0.00 sec)
CREATE TABLE names (id int, name varchar(20));
INSERT INTO names VALUES (1, 'Bob');
INSERT INTO names VALUES (2, 'John');
INSERT INTO names VALUES (3, 'Paul');
S...
Javascript reduce on array of objects
...dyFound = (words, word) => words.includes(word)
? words
: words.concat(word);
const deduplicatedWords = aBunchOfWords.reduce(skipIfAlreadyFound, []);
Providing a count of all words found:
const incrementWordCount = (counts, word) => {
counts[word] = (counts[word] || 0) + 1;
ret...
Why is string concatenation faster than array join?
Today, I read this thread about the speed of string concatenation.
9 Answers
9
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How to add hyperlink in JLabel?
...rther escaping
private static String linkIfy(String s) {
return A_HREF.concat(s).concat(HREF_CLOSED).concat(s).concat(HREF_END);
}
//WARNING
//This method requires that s is a plain string that requires
//no further escaping
private static String htmlIfy(String s) {
return HTML.concat(s).co...
Insert a row to pandas dataframe
...
Not sure how you were calling concat() but it should work as long as both objects are of the same type. Maybe the issue is that you need to cast your second vector to a dataframe? Using the df that you defined the following works for me:
df2 = pd.DataFra...
Hidden Features of MySQL
...ntryCode,Language)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
Feature: GROUP_CONCAT() aggregate function
Creates a concatenated string of its arguments per detail, and aggregates by concatenating those per group.
Example 1: simple
SELECT CountryCode
, GROUP_CONCAT(Language) AS List
FROM ...
selecting unique values from a column
...you also want to output products details per date as JSON.
SELECT `date`,
CONCAT('{',GROUP_CONCAT('{\"id\": \"',`product_id`,'\",\"name\": \"',`product_name`,'\"}'),'}') as `productsJSON`
FROM `buy` group by `date`
order by `date` DESC
product_id product_name date
| 1 | azd |...
pandas three-way joining multiple dataframes on columns
...dataframes). It's worth noting that if your join keys are unique, using pd.concat will result in simpler syntax: pd.concat([df.set_index('name') for df in dfs], axis=1, join='inner').reset_index(). concat is also more versatile when dealing with duplicate column names across multiple dfs (join isn't...
How to get the first and last date of the current year?
...
To get the first and the last day of the year, one can use the CONCAT function. The resulting value may be cast to any type.
CONCAT(YEAR(Getdate()),'-01-01') FirstOfYear,
CONCAT(YEAR(GETDATE()),'-12-31') LastOfYear
...
How do I convert from BLOB to TEXT in MySQL?
...
This works great for those GROUP_CONCATs that convert your output to blobs and you really want them as strings. I had an issue similar to the OP's while using Node.JS with the node-mysql library - this fixed all group_concat issues.
– m...