This tag refers to the process of removing or deleting data, text, files, or memory.
Questions tagged [erase]
739 questions
6
votes
0 answers
Image gets blurry and zoomed out when erasing
I am using functionality of erasing image and my code is like below. You can see Video HERE. Here current_sticker_img is my Imageview
NOTE: I am also using Pan Gesture for zooming image
//MARK: Eraser touch event
override func touchesBegan(_…
Jitendra Modi
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6
votes
1 answer
std::map Known-Position Erase Amortized Complexity And Number of Red-Black Tree Recolorings
The complexity of std::map::erase(iterator) is amortized O(1) (see here, for example). While the standard library does not dictate implementations, this de-facto means that the number of rebalancing operations needed for a red-black tree is…
Ami Tavory
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6
votes
3 answers
which one is faster using erase or resize in a vector?
In the following code which one is more efficient calling resize or erase ?
vector a(5000);
//....
vector::iterator it = remove(a.begin(),a.end(),8)
a.resize( std::distance(a.begin(),it));
//or
a.erase(it,a.end());
I think it depends on…
uchar
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6
votes
2 answers
string::erase(0) on an empty string?
Is the behaviour of std::string::erase(0) is well defined on an empty string. Because cppreference says:
Removes count characters starting at index.
But for an empty string, the character at index 0 does not exist.
Vincent
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6
votes
4 answers
Remove characters from std::string from "(" to ")" with erase ?
I want to remove the substring of my string , it looks something like this :
At(Robot,Room3)
or
SwitchOn(Room2)
or
SwitchOff(Room1)
How can I remove all the characters from the left bracket ( to the right bracket ) , when I don't know their…
JAN
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5
votes
1 answer
Why do associative containers have an erase overload with non-const iterator argument?
C++11 changed std::vector::erase to take a const_iterator instead of an iterator. The same thing applies to std::deque and std::list, while std::forward_list came in C++11 with erase_after, which also takes a const_iterator.
In contrast,…
Nelfeal
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5
votes
3 answers
Will the erase function of set in C++ change the address of other elements?
I have the following code:
set test;
test.insert(key1);
test.insert(key2);
iter1 = test.find(key1);
iter2 = test.find(key2);
test.erase(iter1);
My question is, if key1 is deleted, now can I use iter2 to refer to key2 in test?
Thanks
cheng
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5
votes
3 answers
Deleting user-defined elements in the middle of a vector
I'm coding a program where I want to draw a card, and then delete so that it doesn't get drawn again.
I have a vector of Cards (class containing 2 structs that define Suit and Value) called deck and I don't really know how to use iterators very…
Jota
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5
votes
5 answers
Doesn't erasing std::list::iterator invalidates the iterator and destroys the object?
Why does the following print 2?
list l;
l.push_back( 1 );
l.push_back( 2 );
l.push_back( 3 );
list::iterator i = l.begin();
i++;
l.erase( i );
cout << *i;
I know what erase returns, but I wonder why this is OK? Or is it undefined, or does…
Kiril Kirov
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5
votes
5 answers
vectors: rend() is being invalidated by erase()
According to the C++ specification (23.2.4.3), vector::erase() only invalidates "all the iterators and references after the point of the erase"
As such, when using reverse_iterators to pass over all vector members, an erase on the current iterator…
Mahmoud Al-Qudsi
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5
votes
1 answer
JavaFX: Erase Line by painting
i'm new to JavaFX and i'm trying to draw some things on a canvas.
First I'm setting the linecolor to black and draw a line.
canvas.getGraphicsContext2D().setStroke(Color.BLACK);
canvas.getGraphicsContext2D().strokeLine(20,20,100,100);
After this…
Ma Sch
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5
votes
4 answers
Problem with invalidation of STL iterators when calling erase
The STL standard defines that when an erase occurs on containers such as std::deque, std::list etc iterators are invalidated.
My question is as follows, assuming the list of integers contained in a std::deque, and a pair of indicies indicating a…
Matthieu N.
5
votes
6 answers
How can I free a pointer vector?
How can I free up memory in a pointer vector?
Here's the code:
class A
{
private:
int x,y,z;
public:
A(param1, param2, param3)
{
x=param1;
y=param2;
z=param3;
}
…
Tibor
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5
votes
1 answer
calling .clear() or .erase() on c++ std::multimap sometimes causes freeze (100% cpu)
We are using a multimap for quick value/index lookups, declared like this
typedef double Numerical;
std::multimap SortableRowIndex;
And we fill it up with pairs, using
SortableRowIndex.insert(std::pair
Linus Särnhult
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- 3
5
votes
5 answers
Erasing elements from a vector, if they are also in another vector
Suppose I've a vector a = {"the", "of"} and a vector b = {"oranges", "the", "of", "apples"}.
I want to compare both vectors and remove the elements from a which are also in b. This is what I came up with:
for (int i = 0; i < a.size(); i++) {
for…
muqsitnawaz
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