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Add one row to pandas DataFrame
... It is worth noting however, that concat (and therefore append) makes a full copy of the data, and that constantly reusing this function can create a significant performance hit. If you need to use the operation over several datasets, use a list comprehension...
How to write to an existing excel file without overwriting data (using pandas)?
...iteration you append the dataframe to a list. In the end you only need to concat. If they follow the same structure will work as a charm. list_my_dfs = [df1, df2, ...] # List of your dataframes my_dfs_together = pd.concat(list_my_df ) # concat my dataframes in a single df
– ...
Algorithm to return all combinations of k elements from n
...
elements.Skip(i + 1).Combinations(k - 1).Select(c => (new[] {e}).Concat(c)));
}
Usage:
var result = Combinations(new[] { 1, 2, 3, 4, 5 }, 3);
Result:
123
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Java equivalent to Explode and Implode(PHP) [closed]
.... so you can use
subString/split
for Explode & use String
concate
for Implode.
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For loop example in MySQL
... declare x INT default 0;
SET x = 1;
WHILE x <= 5 DO
SET str = CONCAT(str,x,',');
SET x = x + 1;
END WHILE;
select str;
END//
Which prints:
mysql> call while_example();
+------------+
| str |
+------------+
| 1,2,3,4,5, |
+------------+
REPEAT loop syntax example ...
Delete the first three rows of a dataframe in pandas
... @M.K if using this approach, you can use this in combination with pd.concat(). Something like, df2 = pd.concat([df.iloc[:3],df.iloc[10:]]).
– bdiamante
Jun 26 '19 at 17:00
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How to get all columns' names for all the tables in MySQL?
...omma-delimited list of the columns in each table:
SELECT table_name,GROUP_CONCAT(column_name ORDER BY ordinal_position)
FROM information_schema.columns
WHERE table_schema = DATABASE()
GROUP BY table_name
ORDER BY table_name
Note : When using tables with a high number of columns and/or with long f...
MySQL search and replace some text in a field
...t to search and replace based on the value of another field you could do a CONCAT:
update table_name set `field_name` = replace(`field_name`,'YOUR_OLD_STRING',CONCAT('NEW_STRING',`OTHER_FIELD_VALUE`,'AFTER_IF_NEEDED'));
Just to have this one here so that others will find it at once.
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How to convert an int array to String with toString method in Java [duplicate]
...
.mapToObj(String::valueOf)
.reduce((a, b) -> a.concat(",").concat(b))
.get();
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How to see indexes for a database or table in MySQL?
...ed database.
SELECT TABLE_NAME,
COUNT(1) index_count,
GROUP_CONCAT(DISTINCT(index_name) SEPARATOR ',\n ') indexes
FROM INFORMATION_SCHEMA.STATISTICS
WHERE TABLE_SCHEMA = 'mydb'
AND INDEX_NAME != 'primary'
GROUP BY TABLE_NAME
ORDER BY COUNT(1) DESC;
...