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Pass ruby script file to rails console
Is there a way to pass ruby file, foo.rb to rails console. Expected results would be after console starts rails environment to run file.
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Elegant Python function to convert CamelCase to snake_case?
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name = pattern.sub('_', name).lower()
To handle more advanced cases specially (this is not reversible anymore):
def camel_to_snake(name):
name = re.sub('(.)([A-Z][a-z]+)', r'\1_\2', name)
return re.sub('([a-z0-9])([A-Z])', r'\1_\2', name).lower()
print(camel_to_snake('camel2_camel2_case')) #...
PHP Fatal error: Cannot redeclare class
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It means you've already created a class.
For instance:
class Foo {}
// some code here
class Foo {}
That second Foo would throw the error.
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When should you not use virtual destructors?
...o not declare a virtual destructor for a class? When should you specifically avoid writing one?
12 Answers
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Selecting multiple columns in a pandas dataframe
...).
df1 = df[['a', 'b']]
Alternatively, if it matters to index them numerically and not by their name (say your code should automatically do this without knowing the names of the first two columns) then you can do this instead:
df1 = df.iloc[:, 0:2] # Remember that Python does not slice inclusive of...
Should a return statement be inside or outside a lock?
...d then returning it (outside the lock), then I'd say that a simple "return foo" inside the lock is a lot simpler.
To show the difference in IL, lets code:
static class Program
{
static void Main() { }
static readonly object sync = new object();
static int GetValue() { return 5; }
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Get keys from HashMap in Java
...HashMap contains more than one key. You can use keySet() to get the set of all keys.
team1.put("foo", 1);
team1.put("bar", 2);
will store 1 with key "foo" and 2 with key "bar". To iterate over all the keys:
for ( String key : team1.keySet() ) {
System.out.println( key );
}
will print "foo"...
Explain the encapsulated anonymous function syntax
...ression:
(function foo() {
alert(2 + 2);
}());
The Parentheses (formally called the Grouping Operator) can surround only expressions, and a function expression is evaluated.
The two grammar productions can be ambiguous, and they can look exactly the same, for example:
function foo () {} // ...
What is the purpose of the single underscore “_” variable in Python?
...cate that part
of a function result is being deliberately ignored (Conceptually, it is being discarded.), as in code like:
label, has_label, _ = text.partition(':').
As part of a function definition (using either def or lambda), where
the signature is fixed (e.g. by a callback or parent class API), ...
How does Apple know you are using private API?
...since I do not work in the Apple review team.
1. otool -L
This will list all libraries the app has linked to. Something clearly you should not use, like IOKit and WebKit can be detected by this.
2. nm -u
This will list all linked symbols. This can detect
Undocumented C functions such as _UIIma...