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Why .NET String is immutable? [duplicate]
... before StringBuilder becomes more efficient than the equivalent series of concatenations, with their inherent construction).
It would be a disadvantage if mutability was part of the purpose of an object (who'd want to be modeled by an Employee object whose salary could never ever change) though so...
Convert int to string?
... containing your integer; and then create a 3rd string that contains the 2 concated. string.Format("xyz{0}", i); on the other hand, is able to produce just 2 strings - as it's concatting them inline. This performance becomes more noticeable as the strings get longer.
– UKMonk...
Get table column names in MySQL?
...
How about this:
SELECT @cCommand := GROUP_CONCAT( COLUMN_NAME ORDER BY column_name SEPARATOR ',\n')
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = 'my_database' AND TABLE_NAME = 'my_table';
SET @cCommand = CONCAT( 'SELECT ', @cCommand, ' from my_database.my_t...
SQL order string as number
... leading zeros to make all integer strings having equal length.
ORDER BY CONCAT( REPEAT( "0", 18 - LENGTH( stringfield ) ) , stringfield )
or order by part of a field something like 'tensymbols13', 'tensymbols1222' etc.
ORDER BY CONCAT( REPEAT( "0", 18 - LENGTH( LEFT( stringfield , 10 ) ) ) ...
Alter MySQL table to add comments on columns
...
Script for all fields on database:
SELECT
table_name,
column_name,
CONCAT('ALTER TABLE `',
TABLE_SCHEMA,
'`.`',
table_name,
'` CHANGE `',
column_name,
'` `',
column_name,
'` ',
column_type,
' ',
IF(is_nul...
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...
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 ...
Compare two DataFrames and output their differences side-by-side
....
Using the example data from the original question
The first step is to concatenate the DataFrames horizontally with the concat function and distinguish each frame with the keys parameter:
df_all = pd.concat([df.set_index('id'), df2.set_index('id')],
axis='columns', keys=['Fi...
BestPractice - Transform first character of a string into lower case
...
I would use simple concatenation:
Char.ToLowerInvariant(name[0]) + name.Substring(1)
The first solution is not optimized because string.Format is slow and you don't need it if you have a format that will never change. It also generates an ex...
What purpose does a tag serve inside of a tag?
... systemPage = js;
} else if (key) {
others = others.concat(js);
} else {
inline = inline.concat(js);
}
}
}
for (var i = 0; i < scripts.length; s++) {
var script = scripts[i];
var src = script.src;
if (!isListed(src...