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Why is lock(this) {…} bad?
...ns, special care should be taken to consider possible deadlock situations, and having an unknown number of lock entry points hinders this. For example, any one with a reference to the object can lock on it without the object designer/creator knowing about it. This increases the complexity of multi-t...
How to automatically add user account AND password with a Bash script?
I need to have the ability to create user accounts on my Linux (Fedora 10) and automatically assign a password via a bash script(or otherwise, if need be).
...
How to merge dictionaries of dictionaries?
...for key in b:
if key in a:
if isinstance(a[key], dict) and isinstance(b[key], dict):
merge(a[key], b[key], path + [str(key)])
elif a[key] == b[key]:
pass # same leaf value
else:
raise Exception('Conflict at %...
Linear Regression and group by in R
...ction. My data is an annual time series with one field for year (22 years) and another for state (50 states). I want to fit a regression for each state so that at the end I have a vector of lm responses. I can imagine doing for loop for each state then doing the regression inside the loop and adding...
List changes unexpectedly after assignment. How do I clone or copy it to prevent this?
... any modifications to new_list changes my_list everytime. Why is this, and how can I clone or copy the list to prevent it?
...
When and why would you seal a class?
In C# and C++/CLI the keyword sealed (or NotInheritable in VB) is used to protect a class from any inheritance chance (the class will be non-inheritable). I know that one feature of object-oriented programming is inheritance and I feel that the use of sealed goes against this feature, it stop...
How do you know when to use fold-left and when to use fold-right?
I'm aware that fold-left produces left-leaning trees and fold-right produces right-leaning trees, but when I reach for a fold, I sometimes find myself getting bogged down in headache-inducing thought trying to determine which kind of fold is appropriate. I usually end up unwinding the entire proble...
How does this program work?
...er. The default argument promotions are performed on trailing arguments.
and from 6.5.2.2/6,
If the expression that denotes the called function has a type that does not include a prototype, the integer promotions are performed on each argument, and arguments that have type float are promoted t...
How to prevent XSS with HTML/PHP?
How do I prevent XSS (cross-site scripting) using just HTML and PHP?
9 Answers
9
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How can I make grep print the lines below and above each matching line? [duplicate]
I have to parse a very large file and I want to use the command grep (or any other tool).
3 Answers
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