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What does @: (at symbol colon) mean in a Makefile?
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It means "don't echo this command on the output." So this rule is saying "execute the shell command : and don't echo the output.
Of course the shell command : is a no-op, so this is saying "do nothing, and don't tell."
Why?
The trick here is that you'...
How does tuple comparison work in Python?
I have been reading the Core Python programming book, and the author shows an example like:
4 Answers
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Is if(items != null) superfluous before foreach(T item in items)?
...e idea; an empty array would be preferable because it consumes less memory and produces less memory pressure. Enumerable.Empty<string> would be even more preferable because it caches the empty array it generates and re-uses it.
– Eric Lippert
Jun 23 '11 a...
How to create duplicate allowed attributes
... AttributeUsage attribute onto your Attribute class (yep, that's mouthful) and set AllowMultiple to true:
[AttributeUsage(AttributeTargets.Method, AllowMultiple = true)]
public sealed class MyCustomAttribute: Attribute
sha...
apache redirect from non www to www
...ame www.example.com
# real server configuration
</VirtualHost>
And then you'll have another <VirtualHost> section with ServerName www.example.com for your real server configuration. Apache automatically preserves anything after the / when using the Redirect directive, which is a co...
add maven repository to build.gradle
I added a custom maven repository to build.gradle in Android Studio but the dependency is not being found
5 Answers
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What are the sizes used for the iOS application splash screen?
... Human Interface Guidelines - Launch Screens for details on launch screens and recommendations.
Thanks
Drekka
July 2012 - As this reply is rather old, but stills seems popular. I've written a blog post based on Apple's doco and placed it on my blog. I hope you guys find it useful.
Yes. In iPhone/iP...
Pandas conditional creation of a series/dataframe column
...color'] = np.where(df['Set']=='Z', 'green', 'red')
For example,
import pandas as pd
import numpy as np
df = pd.DataFrame({'Type':list('ABBC'), 'Set':list('ZZXY')})
df['color'] = np.where(df['Set']=='Z', 'green', 'red')
print(df)
yields
Set Type color
0 Z A green
1 Z B green
2 ...
Authorize a non-admin developer in Xcode / Mac OS
I use a standard user account for my daily tasks on Mac OS. Since upgrading to Snow Leopard I am asked to do the following when a program is run from within Xcode:
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Sequence contains no matching element
...tions are Single() (when you believe there's exactly one matching element) and SingleOrDefault() (when you believe there's exactly one or zero matching elements). I suspect that FirstOrDefault is the best option in this particular case, but it's worth knowing about the others anyway.
On the other h...