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How can I quickly sum all numbers in a file?
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For a Perl one-liner, it's basically the same thing as the awk solution in Ayman Hourieh's answer:
% perl -nle '$sum += $_ } END { print $sum'
If you're curious what Perl one-liners do, you can deparse them:
% perl -MO=Deparse -nle '$sum += $_ } END ...
How to get the Display Name Attribute of an Enum member via MVC razor code?
I've got a property in my model called "Promotion" that its type is a flag enum called "UserPromotion". Members of my enum have display attributes set as follows:
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Is there a cross-browser onload event when clicking the back button?
For all major browsers (except IE), the JavaScript onload event doesn’t fire when the page loads as a result of a back button operation — it only fires when the page is first loaded.
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What is move semantics?
...regarding C++0x . Most of the new features made sense to me, and I am actually excited about C++0x now, with the exception of one. I still don't get move semantics ... What is it exactly?
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How to take all but the last element in a sequence using LINQ?
... using generators (yield return).
public static IEnumerable<T> TakeAllButLast<T>(this IEnumerable<T> source) {
var it = source.GetEnumerator();
bool hasRemainingItems = false;
bool isFirst = true;
T item = default(T);
do {
hasRemainingItems = it.MoveN...
Who architected / designed C++'s IOStreams, and would it still be considered well-designed by today'
... sign of quality design.
IOStreams have a checkered history. They are actually a reworking of an earlier streams library, but were authored at a time when many of today's C++ idioms didn't exist, so the designers didn't have the benefit of hindsight. One issue that only became apparent over time wa...
How to find encoding of a file via script on Linux?
I need to find the encoding of all files that are placed in a directory. Is there a way to find the encoding used?
17 Answe...
What does auto&& tell us?
...value or rvalue expression and I will preserve its constness. This is typically used for forwarding (usually with T&&). The reason this works is because a "universal reference", auto&& or T&&, will bind to anything.
You might say, well why not just use a const auto& beca...
Transpose a data frame
...You'd better not transpose the data.frame while the name column is in it - all numeric values will then be turned into strings!
Here's a solution that keeps numbers as numbers:
# first remember the names
n <- df.aree$name
# transpose all but the first column (name)
df.aree <- as.data.frame(...
Argparse optional positional arguments?
I have a script which is meant to be used like this:
usage: installer.py dir [-h] [-v]
3 Answers
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