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Large, persistent DataFrame in pandas
...o read the file in smaller pieces (use iterator=True, chunksize=1000) then concatenate then with pd.concat. The problem comes in when you pull the entire text file into memory in one big slurp.
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Concat all strings inside a List using LINQ
Is there any easy LINQ expression to concatenate my entire List<string> collection items to a single string with a delimiter character?
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Spring JPA @Query with LIKE
...orks for me):
@Query("SELECT u.username FROM User u WHERE u.username LIKE CONCAT('%',:username,'%')")
List<String> findUsersWithPartOfName(@Param("username") String username);
Notice: The table name in JPQL must start with a capital letter.
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StringBuilder vs String concatenation in toString() in Java
...s it might not make a
difference, but at what point do you
switch from concat to builder?
At the point where you're concatenating in a loop - that's usually when the compiler can't substitute StringBuilder by itself.
s...
How do I quickly rename a MySQL database (change schema name)?
...ginally suggested the former and someone "improved" my answer to use GROUP_CONCAT. Take your pick, but I prefer the original):
SELECT CONCAT('RENAME TABLE $1.', table_name, ' TO $2.', table_name, '; ')
FROM information_schema.TABLES
WHERE table_schema='$1';
or
SELECT GROUP_CONCAT('RENAME TABLE ...
What's the best name for a non-mutating “add” method on an immutable collection?
...
In situations like that, I usually go with Concat. That usually implies to me that a new object is being created.
var p = listA.Concat(listB);
var k = listA.Concat(item);
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MySQL JOIN the most recent row only?
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You may want to try the following:
SELECT CONCAT(title, ' ', forename, ' ', surname) AS name
FROM customer c
JOIN (
SELECT MAX(id) max_id, customer_id
FROM customer_data
GROUP BY customer_id
) c...
In MySQL, can I copy one row to insert into the same table?
...
SET @temptable = '_duplicate_temp_table';
SET @sql_text = CONCAT('CREATE TABLE ', @temptable, ' LIKE ', copytable);
PREPARE stmt FROM @sql_text;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
SET @sql_text = CONCAT('INSERT INTO ', @temptable, ' SELECT * FROM ...
How is null + true a string?
...e compiler, it's actually able to compile the above as:
string x = string.Concat(a, b, c, d);
which can create just a single string of exactly the right length, copying all the data exactly once. Nice.
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Create JSON object dynamically via JavaScript (Without concate strings)
...estions%2f16507222%2fcreate-json-object-dynamically-via-javascript-without-concate-strings%23new-answer', 'question_page');
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