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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 ...
Reading a huge .csv file
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You are reading all rows into a list, then processing that list. Don't do that.
Process your rows as you produce them. If you need to filter the data first, use a generator function:
import csv
def getstuff(filename, criterion):
with ...
Where can I get a list of Ansible pre-defined variables?
...h0.ipv4.address. Googleing and searching the docs I cound't find a list of all available variables. Would someone list them for me?
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How to work with complex numbers in C?
...h:
creal(z1): get the real part (for float crealf(z1), for long double creall(z1))
cimag(z1): get the imaginary part (for float cimagf(z1), for long double cimagl(z1))
Another important point to remember when working with complex numbers is that functions like cos(), exp() and sqrt() must be repl...
What are the rules about using an underscore in a C++ identifier?
...FC background, you'll probably use m_foo . I've also seen myFoo occasionally.
5 Answers
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What's the difference between a Python “property” and “attribute”?
I am generally confused about the difference between a "property" and an "attribute", and can't find a great resource to concisely detail the differences.
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Delimiters in MySQL
...s it through a programming language API to MySQL. Some other clients like PHPMyAdmin have other methods to specify a non-default delimiter.
Example:
DELIMITER $$
/* This is a complete statement, not part of the procedure, so use the custom delimiter $$ */
DROP PROCEDURE my_procedure$$
/* Now start...
Converting any string into camel case
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Looking at your code, you can achieve it with only two replace calls:
function camelize(str) {
return str.replace(/(?:^\w|[A-Z]|\b\w)/g, function(word, index) {
return index === 0 ? word.toLowerCase() : word.toUpperCase();
}).replace(/\s+/g, '');
}
camelize("EquipmentClass name"...
Python debugging tips [closed]
... same effect in the running code
ipdb is a version of pdb for IPython. It allows the use of pdb with all the IPython features including tab completion.
It is also possible to set pdb to automatically run on an uncaught exception.
Pydb was written to be an enhanced version of Pdb. Benefits?
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Adding Core Data to existing iPhone project
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All the CoreData header files are imported in App_Prefix.pch, so the CoreData classes will be available throughout your Project, so you don't have to manually import the header in the files you need them.
So open up Xcode an...