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Is there a performance difference between a for loop and a for-each loop?
... iterator or index variable
completely. The resulting idiom
applies equally to collections and
arrays:
// The preferred idiom for iterating over collections and arrays
for (Element e : elements) {
doSomething(e);
}
When you see the colon (:), read it as
“in.” Thus, the loop ab...
How do I correctly clean up a Python object?
...it close() statement is that you have to worry about people forgetting to call it at all or forgetting to place it in a finally block to prevent a resource leak when an exception occurs.
To use the with statement, create a class with the following methods:
def __enter__(self)
def __exit__(self...
How do you discover model attributes in Rails?
...ructure:
ActiveRecord::Schema.define(version: 20130712162401) do
create_table "users", force: true do |t|
t.string "email", default: "", null: false
t.string "encrypted_password", default: "", null: false
t.string "reset_password_token"
t.datetime "reset...
How update the _id of one MongoDB Document?
I want update an _id field of one document. I know it's not a really good pratice. But with some technical reason, I need update it. If I try to update it I get:
...
Placeholder in UITextView
...
I made a few minor modifications to bcd's solution to allow for initialization from a Xib file, text wrapping, and to maintain background color. Hopefully it will save others the trouble.
UIPlaceHolderTextView.h:
#import <Foundation/Foundation.h>
IB_DESIGNABLE
@interfac...
Does using “new” on a struct allocate it on the heap or stack?
...hen you create an instance of a class with the new operator, memory gets allocated on the heap. When you create an instance of a struct with the new operator where does the memory get allocated, on the heap or on the stack ?
...
Intelligent point label placement in R
...cates, and I think solutions involving hand-labeling deserve a seat at the table, that's all.
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When should iteritems() be used instead of items()?
Is it legitimate to use items() instead of iteritems() in all places? Why was iteritems() removed from Python 3? Seems like a terrific and useful method. What's the reasoning behind it?
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Get position/offset of element relative to a parent container?
...ch mobiles do not support it I would be interested (can't find any support table for mobiles about it).
– Nobita
Jul 1 '14 at 11:54
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How to len(generator()) [duplicate]
...
Generators have no length, they aren't collections after all.
Generators are functions with a internal state (and fancy syntax). You can repeatedly call them to get a sequence of values, so you can use them in loop. But they don't contain any elements, so asking for the length of ...