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C++ How to enumerate QGraphicsItem's?


C++ How to enumerate QGraphicsItem's?

By : user2950039
Date : November 17 2020, 11:52 AM
wish helps you Using this function, I can delete selected QGraphicsItem's from a QGraphicsView. How can I get my ellipses enumerated in order to receive a notification like "Deleted ellipse n°...". , A few ways
Assuming you only care about that iteration:
code :
   int ix = 0; // add this
   foreach (QGraphicsItem *item, scene->selectedItems()) {
        if (item->type() == ellipse->Type) {
            scene->removeItem(item);
            delete item;
            std::cout << "Deleted ellipse number " << ix++ << std::endl; // and add this
            QMessageBox::information(this,"Notification", "Deleted");
        }
    }
std::unordered_map<QGraphicsItem*, int> mGraphicsItems;
class MyGraphicsItem : public QGraphicsItem
{
    Q_OBJECT
public:
     // snip
    int index() const { return mIndex; }
    void setIndex( int i ) { mIndex = i; }
private:
    int mIndex;
};


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Flask cannot import enumerate? UndefinedError: 'enumerate' is undefined

Flask cannot import enumerate? UndefinedError: 'enumerate' is undefined


By : user2766195
Date : March 29 2020, 07:55 AM
wish help you to fix your issue As Or Duan says, Jinja2 has its own language. Looks like Python but it's not Python. So the Python enumerate built-in function is not part of Jinja2 template engine. There are, however, some alternatives you can use:
If you want to enumerate the items in a list you can use the loop.index0 loop special variable:
code :
>>> from jinja2 import Template

>>> t1 = """
... {% for val in ['a', 'b', 'c'] %}
...     <td>
...         {{ loop.index0 }} {{ val }}
...     </td>
... {% endfor %}
... """
>>> Template(t1).render()
>>> t2 = """
... {% for i, val in l %}
...     <td>
...         {{ i }} {{ val }}
...     </td>
... {% endfor %}
... """
>>> Template(t2).render(l=enumerate(['a', 'b', 'c']))
>>> t3 = """
... {% for i, val in enumerate(['a', 'b', 'c']) %}
...     <td>
...         {{ i }} {{ val }}
...     </td>
... {% endfor %}
... """
>>> Template(t3).render(enumerate=enumerate)
@app.context_processor
def inject_enumerate():
    return dict(enumerate=enumerate)
How can I skip QGraphicsItems obscured by identical QGraphicsItems?

How can I skip QGraphicsItems obscured by identical QGraphicsItems?


By : Subu
Date : March 29 2020, 07:55 AM
This might help you
If I increase slightly the size of the rectangle on top, the isObscured function works (either version). But with identical shapes, one on top of the other, logically the bottom one would still be obscured...
Swift 2.0 : 'enumerate' is unavailable: call the 'enumerate()' method on the sequence

Swift 2.0 : 'enumerate' is unavailable: call the 'enumerate()' method on the sequence


By : user3771683
Date : March 29 2020, 07:55 AM
I hope this helps . Many global functions have been replaced by protocol extension methods, a new feature of Swift 2, so enumerate() is now an extension method for SequenceType:
code :
extension SequenceType {
    func enumerate() -> EnumerateSequence<Self>
}
let mySwiftStringArray = [ "foo", "bar" ]
for (index, string) in mySwiftStringArray.enumerate() {
   print(string) 
}
let myString = "foo"
let stringLength = myString.characters.count
print(stringLength)
let mySwiftStringArray = [ "foo", "bar" ]
for (index, string) in mySwiftStringArray.enumerated() {
    print(string)
}
enumerate is unavailable call the enumerate method on the sequence

enumerate is unavailable call the enumerate method on the sequence


By : Pushpak Pimpale
Date : March 29 2020, 07:55 AM
To fix the issue you can do In Swift 2, enumerate is not a global function anymore, it's an extension of SequenceType.
Call it directly on the sequence to enumerate like this:
code :
for (index, key) in row.enumerate() {
    // ...
}
How to make code that's functionally similar to enumerate without actually using enumerate?

How to make code that's functionally similar to enumerate without actually using enumerate?


By : Home Jade
Date : March 29 2020, 07:55 AM
around this issue enumerate(sequence) is pretty much similar to a construct of the form:
code :
for i in range(len(sequence)):
    # get sequence[i] and return i and sequence[i] for all i's
for i in range(len(xs)):
    x = xs[i]             
    if v == x:
        count += 1
        if count == 2:
            return i
for i in range(len(xs)):           
    if v == xs[i]:
        count += 1
        if count == 2:
            return i
def my_enumerate(sequence, start=0):
    for i in range(len(sequence)):
        yield start+i, sequence[i]
def my_enumerate(sequence, start=0):
    return [(start+i, sequence[i]) for i in range(len(sequence))]
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