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Mysql error 1452 - Cannot add or update a child row: a foreign key constraint fails
...was fine from the mysql point of view(both tables should use InnoDB engine and the datatype of each column should be of the same type which takes part in foreign key constraint).
The only thing that I did was to disable the foreign key check and later on enabled it after performing the foreign key o...
How to “perfectly” override a dict?
..._contains__
# free setdefault, __eq__, and so on
import pickle
# works too since we just use a normal dict
assert pickle.loads(pickle.dumps(s)) == s
I wouldn't subclass dict (or other builtins) directly. It often makes no sense, because what you actually want t...
How to overlay one div over another div
...gt;
</div>
I would suggest learning about position: relative and child elements with position: absolute.
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UIViewController viewDidLoad vs. viewWillAppear: What is the proper division of labor?
...pushed, viewWillAppear is called. If you push another subview from there, and the user returns, viewWillAppear is called again.
– Kendall Helmstetter Gelner
Oct 16 '09 at 19:52
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Big O, how do you calculate/approximate it?
Most people with a degree in CS will certainly know what Big O stands for .
It helps us to measure how well an algorithm scales.
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gdb: how to print the current line or find the current line number?
list commands prints a set of lines, but I need one single line, where I am and where an error has probably occurred.
5 An...
Trigger a Travis-CI rebuild without pushing a commit?
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I have found and used that in other cases. But I could have sworn I had a case where it had Errored for the reason I described above, and the gear menu lacked that option. Perhaps that was a one-time fluke, or perhaps I was mistaken. Anyw...
What's the difference between String(value) vs value.toString()
Javascript has lot's of "tricks" around types and type conversions so I'm wondering if these 2 methods are the same or if there is some corner case that makes them different?
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open read and close a file in 1 line of code
...lose it for various reasons.
So, what you can do to keep it short, simple and explicit:
with open('pagehead.section.htm','r') as f:
output = f.read()
Now it's just two lines and pretty readable, I think.
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Which exception should I raise on bad/illegal argument combinations in Python?
...tion..
def import_to_orm(name, save=False, recurse=False):
if recurse and not save:
raise ValueError("save must be True if recurse is True")
There's really no point in doing class BadValueError(ValueError):pass - your custom class is identical in use to ValueError, so why not use that...