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MongoDB: Combine data from multiple collections into one..how?
...ns). You need to have some key in both collections that you can use as an _id.
For example, let's say you have a users collection and a comments collection and you want to have a new collection that has some user demographic info for each comment.
Let's say the users collection has the following ...
Define css class in django Forms
... of safe fileter and added parenthesis instead of colon {{ myform.email|add_class("css_class_1 css_class_2")|safe }} thanks for writing this. it should be part of Django.
– David Dehghan
Feb 28 '13 at 10:07
...
Commenting in a Bash script inside a multiline command
...utput MYSQLDUMP file
cat ${MYSQLDUMP} | \
# simplify the line
sed '/created_at/d' | \
# create some newlines
tr ",;" "\n" | \
# use some sed magic
sed -e 's/[asbi]:[0-9]*[:]*//g' -e '/^[{}]/d' -e 's/""//g' -e '/^"{/d' | \
# more magic
sed -n -e '/^"/p' -e '/^print_value$/,/^option_id$/p' | \
# even ...
How to use the pass statement?
...that you don't want to implement, yet.
class MyClass(object):
def meth_a(self):
pass
def meth_b(self):
print "I'm meth_b"
If you were to leave out the pass, the code wouldn't run.
You would then get an:
IndentationError: expected an indented block
To summarize, the pa...
private[this] vs private
...nt type T occurs in contravariant position in type Option[T] of value value_=
class Holder[+T] (initialValue: Option[T]) {
This error occurs because value is a mutable variable on the covariant type T (+T) which is normally a problem unless marked as private to the instance with private[this...
Replacing Spaces with Underscores
I have a PHP Script that users will enter a name like: Alex_Newton ,
12 Answers
12
...
How do I create an average from a Ruby array?
...
Try this:
arr = [5, 6, 7, 8]
arr.inject{ |sum, el| sum + el }.to_f / arr.size
=> 6.5
Note the .to_f, which you'll want for avoiding any problems from integer division. You can also do:
arr = [5, 6, 7, 8]
arr.inject(0.0) { |sum, el| sum + el } / arr.size
=> 6.5
You can define it...
What are the applications of binary trees?
...oving from one level to the next requires one comparison, and there are log_2(m) levels, for a total of log_2(m) comparisons.
In contrast, an n-ary tree will require log_2(n) comparisons (using a binary search) to move to the next level. Since there are log_n(m) total levels, the search will requi...
腾讯Tencent开源框架介绍（持续更新） - 开源 & Github - 清泛网 - 专注C/C++及内核技术
...h>
#include <stdio.h>
#include <stdlib.h>
#include <queue>
#include "co_routine.h"
using namespace std;
/**
* 本实例是对条件变量的展示，其作用类似于pthread_cond_wait
*/
struct stTask_t
{
int id;
};
struct stEnv_t
{
stCoCond_t* cond;
queue<stTask_t*> task_queue...
Creating JS object with Object.create(null)?
...ototype).
In Chrome Devtool you can see that Object.create(null) has no __proto__ property, while {} does.
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