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In Python how should I test if a variable is None, True or False
I have a function that can return one of three things:
6 Answers
6
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Bogus foreign key constraint fail
...eference
The innodb internal data dictionary is out of sync with the mysql one.
You can see which table it was (one of them, anyway) by doing a "SHOW ENGINE INNODB STATUS" after the drop fails.
If it turns out to be the latter case, I'd dump and restore the whole server if you can.
MySQL 5.1 and...
How do I use cascade delete with SQL Server?
I have 2 tables: T1 and T2, they are existing tables with data. We have a one to many relationship between T1 and T2. How do I alter the table definitions to perform cascading delete in SQL Server when a record from T1 is deleted, all associated records in T2 also deleted.
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Convert a list to a data frame
...x means that all data will be coerced into a common type. I.e. if you have one column of character data and one column of numeric data the numeric data will be coerced to string by matrix() and then both to factor by data.frame().
– Ian Sudbery
Mar 15 '13 at 10...
Update just one gem with bundler
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note: this command will update one gem without dependencies of it
– mmike
Jun 4 '18 at 11:07
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How to check if a map contains a key in Go?
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One line answer:
if val, ok := dict["foo"]; ok {
//do something here
}
Explanation:
if statements in Go can include both a condition and an initialization statement. The example above uses both:
initializes two vari...
What is “String args[]”? parameter in main method Java
...String objects.
In other words, if you run your program as java MyProgram one two then args will contain ["one", "two"].
If you wanted to output the contents of args, you can just loop through them like this...
public class ArgumentExample {
public static void main(String[] args) {
fo...
tmux: How to join two tmux windows into one, as panes?
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Actually join-pane is to move one pane into another, not to move window. join-pane -s 2 -t 1 does not put two windows side by side, but two panes instead. It's just that the windows happen to have only one pane each. If you have two windows both of which ...
How to configure git push to automatically set upstream without -u?
... to keep in mind that this does not make the local branch track the remote one; it just creates the remote branch with the same name as the local one.
– waldyrious
Mar 15 '19 at 12:20
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What exactly is Type Coercion in Javascript?
... coercion means that when the operands of an operator are different types, one of them will be converted to an "equivalent" value of the other operand's type. For instance, if you do:
boolean == integer
the boolean operand will be converted to an integer: false becomes 0, true becomes 1. Then the...