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How do I copy a hash in Ruby?
...at clone of a hash makes a shallow copy. That is to say:
h1 = {:a => 'foo'}
h2 = h1.clone
h1[:a] << 'bar'
p h2 # => {:a=>"foobar"}
What's happening is that the hash's references are being copied, but not the objects that the references refer to.
If you want a deep...
Is it possible to roll back CREATE TABLE and ALTER TABLE statements in major SQL databases?
...situations are quite handled- for example, if you try to select from table foo while another transaction is dropping it and creating a replacement table foo, then the blocked transaction will finally receive an error rather than finding the new foo table. (Edit: this was fixed in or before PostgreSQ...
What's the (hidden) cost of Scala's lazy val?
...he bitmap indicates it is necessary.
Using:
class Something {
lazy val foo = getFoo
def getFoo = "foo!"
}
produces sample bytecode:
0 aload_0 [this]
1 getfield blevins.example.Something.bitmap$0 : int [15]
4 iconst_1
5 iand
6 iconst_0
7 if_icmpne 48
10 aload_0 [this]
11 dup
12...
Separation of JUnit classes into special test package?
...they test, but in a different physical directory, like:
myproject/src/com/foo/Bar.java
myproject/test/com/foo/BarTest.java
In a Maven project it would look like this:
myproject/src/main/java/com/foo/Bar.java
myproject/src/test/java/com/foo/BarTest.java
The main point in this is that my test cl...
How to hash a string into 8 digits?
... invocations. See here:
$ python -V
Python 2.7.5
$ python -c 'print(hash("foo"))'
-4177197833195190597
$ python -c 'print(hash("foo"))'
-4177197833195190597
$ python3 -V
Python 3.4.2
$ python3 -c 'print(hash("foo"))'
5790391865899772265
$ python3 -c 'print(hash("foo"))'
-8152690834165248934
This...
Why does git revert complain about a missing -m option?
...
Say the other guy created bar on top of foo, but you created baz in the meantime and then merged, giving a history of
$ git lola
* 2582152 (HEAD, master) Merge branch 'otherguy'
|\
| * c7256de (otherguy) bar
* | b7e7176 baz
|/
* 9968f79 foo
Note: git lola i...
filter items in a python dictionary where keys contain a specific string
...2.7
results = map(some_function, [(k,v) for k,v in a_dict.iteritems() if 'foo' in k])
Now the result will be in a list with some_function applied to each key/value pair of the dictionary, that has foo in its key.
If you just want to deal with the values and ignore the keys, just change the list ...
How can I do something like a FlowLayout in Android?
How can I do something like a FlowLayout in Android?
9 Answers
9
...
Check whether a path is valid in Python without creating a file at the path's target
...s, which frankly bore and anger me in equal measure:
>>> print('"foo.bar" valid? ' + str(is_pathname_valid('foo.bar')))
"foo.bar" valid? True
>>> print('Null byte valid? ' + str(is_pathname_valid('\x00')))
Null byte valid? False
>>> print('Long path valid? ' + str(is_path...
Looking for jQuery find(..) method that includes the current node
...this.pushStack(r);
};
After the call of the end function it returns the #foo element.
$('#foo')
.findBack('.red')
.css('color', 'red')
.end()
.removeAttr('id');
Without defining extra plugins, you are stuck with this.
$('#foo')
.find('.red')
.addBack('.red')
...