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How to keep index when using pandas merge
I would like to merge two DataFrames , and keep the index from the first frame as the index on the merged dataset. However, when I do the merge, the resulting DataFrame has integer index. How can I specify that I want to keep the index from the left data frame?
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Difference between var_dump,var_export & print_r
...2] => 42
[3] => Array ([0] => 42)
)
var_export prints valid php code. Useful if you calculated some values and want the results as a constant in another script. Note that var_export can not handle reference cycles/recursive arrays, whereas var_dump and print_r check for these. var_exp...
How important is the order of columns in indexes?
...should put columns that will be the most selective at the beginning of the index declaration. Example:
5 Answers
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Microsoft Excel mangles Diacritics in .csv files?
I am programmatically exporting data (using PHP 5.2) into a .csv test file.
Example data: Numéro 1 (note the accented e).
The data is utf-8 (no prepended BOM).
...
Does MySQL index foreign key columns automatically?
Does MySQL index foreign key columns automatically?
9 Answers
9
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Handle Guzzle exception and get HTTP body
...ttp\Psr7\Response
* (find it in ./vendor/guzzlehttp/psr7/src/Response.php) with all
* its own and its 'Message' trait's methods. See more explanations below.
*
* So you can have: HTTP status code, message, headers and body.
* Just check the exception object has the response ...
Safe (bounds-checked) array lookup in Swift, through optional bindings?
If I have an array in Swift, and try to access an index that is out of bounds, there is an unsurprising runtime error:
19 A...
Indexes of all occurrences of character in a string
...tions without the -1 at the end that Peter Lawrey's solution has had.
int index = word.indexOf(guess);
while (index >= 0) {
System.out.println(index);
index = word.indexOf(guess, index + 1);
}
It can also be done as a for loop:
for (int index = word.indexOf(guess);
index >= 0;...
How to iterate for loop in reverse order in swift?
....
To iterate on a range in reverse order, they can be used as below:
for index in stride(from: 5, to: 1, by: -1) {
print(index)
}
//prints 5, 4, 3, 2
for index in stride(from: 5, through: 1, by: -1) {
print(index)
}
//prints 5, 4, 3, 2, 1
Note that neither of those is a Range member fun...
How many database indexes is too many?
...that occur on the table.
If there's lots of SELECTs and very few changes, index all you like.... these will (potentially) speed the SELECT statements up.
If the table is heavily hit by UPDATEs, INSERTs + DELETEs ... these will be very slow with lots of indexes since they all need to be modified ea...