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Recursion or Iteration?
Is there a performance hit if we use a loop instead of recursion or vice versa in algorithms where both can serve the same purpose? Eg: Check if the given string is a palindrome.
I have seen many programmers using recursion as a means to show off when a simple iteration algorithm can fit the bill.
D...
What does the 'standalone' directive mean in XML?
...
The standalone declaration is a way of telling the parser to ignore any markup declarations in the DTD. The DTD is thereafter used for validation only.
As an example, consider the humble <img> tag. If you look at the XHTML 1.0 DTD, you see a markup declaration telling the parser th...
What's the difference between an id and a class?
...ic element and class when you have a number of things that are all alike. For instance, common id elements are things like header, footer, sidebar. Common class elements are things like highlight or external-link.
It's a good idea to read up on the cascade and understand the precedence assigned to ...
Set every cell in matrix to 0 if that row or column contains a 0
...the beginning depend on squares in the end. Maybe my 2nd pass can be made more efficient...
import pprint
m = [[1, 0, 1, 1, 0],
[0, 1, 1, 1, 0],
[1, 1, 1, 1, 1],
[1, 0, 1, 1, 1],
[1, 1, 1, 1, 1]]
N = len(m)
### pass 1
# 1 rst line/column
c = 1
for i in range(N):
c &...
What is NODE_ENV and how to use it in Express?
...NV is an environment variable made popular by the express web server framework. When a node application is run, it can check the value of the environment variable and do different things based on the value. NODE_ENV specifically is used (by convention) to state whether a particular environment is a ...
What's the purpose of using braces (i.e. {}) for a single-line if or loop?
...
Let's attempt to also modify i when we increment j:
int j = 0;
for (int i = 0 ; i < 100 ; ++i)
if (i % 2 == 0)
j++;
i++;
Oh no! Coming from Python, this looks ok, but in fact it isn't, as it's equivalent to:
int j = 0;
for (int i = 0 ; i < 100 ; ++i)
if (i...
Limit ggplot2 axes without removing data (outside limits): zoom
...cify axis limits in ggplot the outlying points are removed. This is fine for points, but you might want to plot lines that intersect with the specified range, but ggplot's range or xlim/ylim methods removes these. Is there another way to specify the plot axis range without removing outlying da...
How to write an async method with out parameter?
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You can't have async methods with ref or out parameters.
Lucian Wischik explains why this is not possible on this MSDN thread: http://social.msdn.microsoft.com/Forums/en-US/d2f48a52-e35a-4948-844d-828a1a6deb74/why-async-methods-cannot-have-ref-or-out-parameters
...
String output: format or concat in C#?
Let's say that you want to output or concat strings. Which of the following styles do you prefer?
31 Answers
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Using i and j as variables in Matlab
... i and j are both functions denoting the imaginary unit:
http://www.mathworks.co.uk/help/matlab/ref/i.html
http://www.mathworks.co.uk/help/matlab/ref/j.html
So a variable called i or j will override them, potentially silently breaking code that does complex maths.
Possible solutions include usi...