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Difference between std::result_of and decltype
I have some trouble understanding the need for std::result_of in C++0x. If I understood correctly, result_of is used to obtain the resulting type of invoking a function object with certain types of parameters. For example:
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Convert pem key to ssh-rsa format
I have a certificate in der format, from it with this command I generate a public key:
8 Answers
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Rails raw SQL example
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side note: records_array will be of different types for different database adapters. If you're using PG, it will be an instance of PG::Result, not Array.
– tybro0103
Jan 14 '14 at 17:28
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UITableView load more when scrolling to bottom like Facebook application
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You can do that by adding a check on where you're at in the cellForRowAtIndexPath: method. This method is easy to understand and to implement :
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
// Classic start method
static ...
How to drop unique in MySQL?
... Note that you may not be able to drop a key like this if a foreign key to the email column exists (error 150) . To get this to work, drop the foreign key first, then drop the index, and recreate the foreign key afterwards. e.g ALTER TABLE fuinfo DROP foreign key fk_name_for_email;
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Validating IPv4 addresses with regexp
I've been trying to get an efficient regex for IPv4 validation, but without much luck. It seemed at one point I had had it with (25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?(\.|$)){4} , but it produces some strange results:
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Backbone.js get and set nested object attribute
...problematic because then you might be tempted to do the same type of thing for set, i.e.
this.model.get("obj1").myAttribute1 = true;
But if you do this, you won't get the benefits of Backbone models for myAttribute1, like change events or validation.
A better solution would be to never nest POJS...
Add data annotations to a class generated by entity framework
...f you are using project type which is differ from ASP.NET MVC (when you perform manual data validation) don't forget to register your validators
/* Global.asax or similar */
TypeDescriptor.AddProviderTransparent(
new AssociatedMetadataTypeTypeDescriptionProvider(typeof(Entity), typeof(IEntityM...
Styling multi-line conditions in 'if' statements? [closed]
... cond3 == 'val3' and cond4 == 'val4'):
do_something
Also, don't forget the whitespace is more flexible than you might think:
if (
cond1 == 'val1' and cond2 == 'val2' and
cond3 == 'val3' and cond4 == 'val4'
):
do_something
if (cond1 == 'val1' and cond2 == 'val2...
How to use `subprocess` command with pipes
...module, you have to pass shell=True.
However, this isn't really advisable for various reasons, not least of which is security. Instead, create the ps and grep processes separately, and pipe the output from one into the other, like so:
ps = subprocess.Popen(('ps', '-A'), stdout=subprocess.PIPE)
out...