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How can I obtain the element-wise logical NOT of a pandas Series?
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NumPy is slower because it casts the input to boolean values (so None and 0 becomes False and everything else becomes True).
import pandas as pd
import numpy as np
s = pd.Series([True, None, False, True])
np.logical_not(s)
gives you
0 False
1 ...
The performance impact of using instanceof in Java
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If "object" is an instance of ObjT, casting it is a little faster than doing an instanceof, but the difference my quick test found was 10-20ms over 10,000,000 iterations. If "object" isn't an ObjT, though, catching the exception was over 3000x slower - over 31,...
How do I limit the number of rows returned by an Oracle query after ordering?
...Oracle in this answer).
To answer the original question, here's the query:
SELECT *
FROM sometable
ORDER BY name
OFFSET 20 ROWS FETCH NEXT 10 ROWS ONLY;
(For earlier Oracle versions, please refer to other answers in this question)
Examples:
Following examples were quoted from linked page, in th...
How can I get the SQL of a PreparedStatement?
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It doesn't work and throws ClassCastException: java.lang.ClassCastException: oracle.jdbc.driver.T4CPreparedStatement cannot be cast to com.mysql.jdbc.JDBC4PreparedStatement
– Ercan
Apr 4 '19 at 13:15
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MySQL Insert Where query
...INSERT INTO Users(weight, desiredWeight)
VALUES (160,145)
INSERT using a SELECT statement
INSERT INTO Users(weight, desiredWeight)
SELECT weight, desiredWeight
FROM AnotherTable
WHERE id = 1
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React JSX: selecting “selected” on selected option
In a React component for a <select> menu, I need to set the selected attribute on the option that reflects the application state.
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Nullable vs. int? - Is there any difference?
...tions is clearly named logical. Remember, in C# there are no conversions ("casts") between bool and numeric types!
– Jeppe Stig Nielsen
Aug 14 '15 at 10:41
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Reference alias (calculated in SELECT) in WHERE clause
The calculated value BalanceDue that is set as a variable in the list of selected columns cannot be used in the WHERE clause.
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Multiple select statements in Single query
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SELECT (
SELECT COUNT(*)
FROM user_table
) AS tot_user,
(
SELECT COUNT(*)
FROM cat_table
) AS tot_cat,
(
SELECT COUNT(*)
FROM course_table
) AS tot_course
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How to call any method asynchronously in c#
...t. Have Foo take one input parameter of type object. You'll then have to cast the object to the appropriate type in Foo.
– Denise Skidmore
Mar 2 '17 at 22:50
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