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Difference between dispatch_async and dispatch_sync on serial queue?
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On a serial queue, both tasks are still executed one after the other. In the first case, the caller waits for the first block to finish but doesn't wait for the second block. In the second case, the caller doesn't wait for the first block to finish, but waits for the second...
Why is it bad style to `rescue Exception => e` in Ruby?
...to:
begin
# iceberg!
rescue StandardError => e
# lifeboats
end
One of the few common cases where it’s sane to rescue from Exception is for logging/reporting purposes, in which case you should immediately re-raise the exception:
begin
# iceberg?
rescue Exception => e
# do some l...
Can my enums have friendly names? [duplicate]
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You can use the System.ComponentModel.DataAnnotations and add an display attr. (like: [Display(Name = "This Name doesn't work")])
– Cas Bloem
Jan 18 '16 at 16:17
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Xcode 5: Code signing entitlement errors
...g profile. Just set the project target's provisioning profile to the right one and it'll work.
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Default profile in Spring 3.1
... beans annotated with @Profile("prod") and @Profile("demo") .
The first one, as you can guess :), is used on beans that connect to production DB and second one annotates beans that use some fake DB ( HashMap or whatever)- to make development faster.
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What's the @ in front of a string in C#?
...s ignored.
So "C:\\Users\\Rich" is the same as @"C:\Users\Rich"
There is one exception: an escape sequence is needed for the double quote. To escape a double quote, you need to put two double quotes in a row. For instance, @"""" evaluates to ".
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How can I compare two lists in python and return matches
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Not the most efficient one, but by far the most obvious way to do it is:
>>> a = [1, 2, 3, 4, 5]
>>> b = [9, 8, 7, 6, 5]
>>> set(a) & set(b)
{5}
if order is significant you can do it with list comprehensions like t...
How do you give iframe 100% height [duplicate]
...it with CSS:
<iframe style="position: absolute; height: 100%; border: none"></iframe>
Be aware that this will by default place it in the upper-left corner of the page, but I guess that is what you want to achieve. You can position with the left,right, top and bottom CSS properties.
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Smallest data URI image possible for a transparent image
...H5BAEAAAAALAAAAAABAAEAAAIBRAA7
As another tip, don't omit image/gif as one comment suggests. This will break in several browsers.
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Get top 1 row of each group
... rn = 1
If you expect 2 entries per day, then this will arbitrarily pick one. To get both entries for a day, use DENSE_RANK instead
As for normalised or not, it depends if you want to:
maintain status in 2 places
preserve status history
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As it stands, you preserve status history. If you wa...