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What are the lesser known but useful data structures?
...s are painfully expensive, given that a pointer is generally longer than a char, which is a shame. They're only suitable for certain data-sets.
– Joe
Jan 29 '10 at 12:06
18
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Easiest way to detect Internet connection on iOS?
...std.h>
#include<netdb.h>
Code:
-(BOOL)isNetworkAvailable
{
char *hostname;
struct hostent *hostinfo;
hostname = "google.com";
hostinfo = gethostbyname (hostname);
if (hostinfo == NULL){
NSLog(@"-> no connection!\n");
return NO;
}
else{
...
How to select html nodes by ID with jquery when the id contains a dot?
...
@Tomalak in comments:
since ID selectors must be preceded by a hash #, there should be no ambiguity here
“#id.class” is a valid selector that requires both an id and a separate class to match; it's valid and not always totally redundant.
The correct...
How to get number of rows using SqlDataReader in C#
...reading all rows (and then you might as well store them)
run a specialized SELECT COUNT(*) query beforehand.
Going twice through the DataReader loop is really expensive, you would have to re-execute the query.
And (thanks to Pete OHanlon) the second option is only concurrency-safe when you use a ...
git selective revert local changes from a file
...fore checkout -p was introduced):
You can do it like this:
git add -i
(select the hunks you want to keep)
git commit -m "tmp"
Now you have a commit with only the changes you want to keep, and the rest is unstaged.
git reset --hard HEAD
At this point, uncommitted changes have been discarded...
erb, haml or slim: which one do you suggest? And why? [closed]
...g new (like HAML) I'd go for HAML. It is a lot more ruby-friendly, reduces char count by much and a lot more readable than ERB.
For example (taken from official HAML site):
In ERB your view will look like this:
<div id="profile">
<div class="left column">
<div id="date">&l...
How to avoid warning when introducing NAs by coercion
...t know how to avoid getting a warning when using as.numeric to convert a character vector.
4 Answers
...
How do I get a list of column names from a psycopg2 cursor?
I would like a general way to generate column labels directly from the selected column names, and recall seeing that python's psycopg2 module supports this feature.
...
MySQL DISTINCT on a GROUP_CONCAT()
I am doing SELECT GROUP_CONCAT(categories SEPARATOR ' ') FROM table . Sample data below:
6 Answers
...
Hibernate Criteria returns children multiple times with FetchType.EAGER
....class)
.list();
List result = session.createQuery("select o from Order o left join fetch o.lineItems").list();
All of these examples produce the same SQL statement:
SELECT o.*, l.* from ORDER o LEFT OUTER JOIN LINE_ITEMS l ON o.ID = l.ORDER_ID
Want to know why th...