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get list of pandas dataframe columns based on data type
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320
If you want a list of columns of a certain type, you can use groupby:
>>> df = pd.Da...
Ruby: Change negative number to positive number?
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3 Answers
3
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Warning message: In `…` : invalid factor level, NA generated
... "Type" to be a character.
> fixed <- data.frame("Type" = character(3), "Amount" = numeric(3))
> str(fixed)
'data.frame': 3 obs. of 2 variables:
$ Type : Factor w/ 1 level "": NA 1 1
$ Amount: chr "100" "0" "0"
>
> fixed <- data.frame("Type" = character(3), "Amount" = nume...
What is the proper way to format a multi-line dict in Python?
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I use #3. Same for long lists, tuples, etc. It doesn't require adding any extra spaces beyond the indentations. As always, be consistent.
mydict = {
"key1": 1,
"key2": 2,
"key3": 3,
}
mylist = [
(1, 'hello'),
(...
Python/postgres/psycopg2: getting ID of row just inserted
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3 Answers
3
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What is the correct way to get a subarray in Scala?
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3 Answers
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C pointers : pointing to an array of fixed size
...alizing it, hiding the array type behind a typedef name
typedef int Vector3d[3];
void transform(Vector3d *vector);
/* equivalent to `void transform(int (*vector)[3])` */
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Vector3d vec;
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transform(&vec);
Note additionally that the above code is invariant with relation to Vector3d type b...
Ruby: How to iterate over a range, but in set increments?
...or example:
(10..100).step(10) do |n|
# n = 10
# n = 20
# n = 30
# ...
end
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UPDATE multiple tables in MySQL using LEFT JOIN
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319
UPDATE t1
LEFT JOIN
t2
ON t2.id = t1.id
SET t1.col1 = newvalue
WHERE t2.id...