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Difference between String replace() and replaceAll()
What's the difference between java.lang.String 's replace() and replaceAll() methods,
other than later uses regex? For simple substitutions like, replace . with / ,
is there any difference?
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How to copy a file to multiple directories using the gnu cp command
...args -n 1 cp file1
Will copy file1 to dir1, dir2, and dir3. xargs will call cp 3 times to do this, see the man page for xargs for details.
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fo...
Best way of invoking getter by reflection
...import java.beans.*
for (PropertyDescriptor pd : Introspector.getBeanInfo(Foo.class).getPropertyDescriptors()) {
if (pd.getReadMethod() != null && !"class".equals(pd.getName()))
System.out.println(pd.getReadMethod().invoke(foo));
}
Note that you could create BeanInfo or PropertyDesc...
What does functools.wraps do?
... def with_logging(*args, **kwargs):
print(func.__name__ + " was called")
return func(*args, **kwargs)
return with_logging
then when you say
@logged
def f(x):
"""does some math"""
return x + x * x
it's exactly the same as saying
def f(x):
"""does some math"""
...
How to combine two or more querysets in a Django view?
...sets into a list is the simplest approach. If the database will be hit for all querysets anyway (e.g. because the result needs to be sorted), this won't add further cost.
from itertools import chain
result_list = list(chain(page_list, article_list, post_list))
Using itertools.chain is faster than...
How can I get all the request headers in Django?
I need to get all the Django request headers. From what i've read, Django simply dumps everything into the request.META variable along with a lot aof other data. What would be the best way to get all the headers that the client sent to my Django application?
...
Should Javadoc comments be added to the implementation?
...methods that are implementation only (not overrides), sure, why not, especially if they are public.
If you have an overriding situation and you are going to replicate any text, then definitely not. Replication is a surefire way of causing discrepancies. As a result, users would have a different und...
Can I set a breakpoint on 'memory access' in GDB?
...
What you're looking for is called a watchpoint.
Usage
(gdb) watch foo: watch the value of variable foo
(gdb) watch *(int*)0x12345678: watch the value pointed by an address, casted to whatever type you want
(gdb) watch a*b + c/d: watch an arbitrarily complex expression, valid in the progra...
How to select a single field for all documents in a MongoDB collection?
... include several fields. In the following operation, find() method returns all documents that match the query. In the result set, only the item and qty fields and, by default, the _id field return in the matching documents.
db.inventory.find( { type: 'food' }, { item: 1, qty: 1 } )
In this example ...
Why does this iterative list-growing code give IndexError: list assignment index out of range?
...or l in i:
j.append(l)
Of course, you'd never do this in practice if all you wanted to do was to copy an existing list. You'd just do:
j = list(i)
Alternatively, if you wanted to use the Python list like an array in other languages, then you could pre-create a list with its elements set to ...