Delete a QString From QStringList

[Zunneh]

@KroMignon the example i give was bad

this is the real example, removing names from a QStringList who finish with the letter ' e ' ( if NameList[index].endswith('e') , so there are many names that finish with' e ', removeAll is applied when you know the names, in my case i don't know the Names, the QStringList will append different Names
did you understand ?

[JonB]

@Zunneh
In that case, do use the "reverse iteration" (i.e. counting downward) suggested by @mchinand and as per the for loop line I have written above. So long as the remove you have in the if inside it will only remove one row ( if (whatever) ListName.removeAt(index)) then it is good.

[KroMignon]

@Zunneh said in Delete a QString From QStringList:

this is the real example, removing names from a QStringList who finish with the letter ' e ' ( if NameList[index].endswith('e') , so there are many names that finish with' e ', removeAll is applied when you know the names, in my case i don't know the Names, the QStringList will append different Names
did you understand ?

That is not what you give as implementation!
One possible solution could be using QStringList::filter():

const auto toRemove = ListName.filter(QRegularExpression(".*e"));
for(const auto &item : toRemove)
    ListName.removeAll(item);

or

const QRegularExpression filter(".*e");
for(int idx = 0; idx < ListName.size(); ++idx)
{
    if(ListName.at(idx).contains(filter))
    {
        ListName.remove(idx);
        --idx;
    }
}

[Zunneh]

@KroMignon yeah after asking the question, i was in the kitchen and it comes on my mind to do indexx -- if he delete one item ( like the second solution )
on more question, can we put more than one filter ? for example delete name s who finish with 'e', 'y' and 'm' ??

@JonB i wil try your solution too

finosh wo

Thanks guys :)

[JonB]

@Zunneh said in Delete a QString From QStringList:

on more question, can we put more than one filter ? for example delete name s who finish with 'e', 'y' and 'm' ??

I have not looked to see if accepted, but I would guess either of

const QRegularExpression filter(".*[eym]");
const QRegularExpression filter(".*(e|y|m)");

(I assume you mean "finish with 'e', 'y' or 'm'"!). Regular expression [abc] means any one letter of, (ab|c|def) has to be used if multiple letter sequences required.

[KroMignon]

@Zunneh said in Delete a QString From QStringList:

on more question, can we put more than one filter ? for example delete name s who finish with 'e', 'y' and 'm' ??

This is a regular expression, so it is up to you to set it up to match your needs.
For 'e', 'y' and 'm' it would be: const QRegularExpression filter(".*(e|y|m)");
Take a look at https://www.jrebel.com/sites/rebel/files/pdfs/regular-expressions-cheat-sheet.pdf

[VRonin]

stl-iterators are safe for calling erase on. The Qt functionality is identical to the one of std::vector.
Given a generic function bool shouldIDeleteThisString(const QString&) that returns true if the string should be removed from the list you can use:

for(auto i = list.begin(); i!=list.end();){
    if(shouldIDeleteThisString(*i))
        i=list.erase(i);
    else
        ++i;
}

[Christian Ehrlicher]

@VRonin since you're doing iterator fun:

list.erase(std::remove_if(list.begin(), list.end(), shouldIDeleteThisString), list.end());

[JonB]

@Christian-Ehrlicher
Indeed, because I looked it up, but it doesn't make it readable, or the way it works very intelligible, IMHO! :)

[aha_1980]

@JonB

but it doesn't make it readable

Get used to it, that's the preferred C++ way nowadays ("functional programming").

Regards

[kshegunov]

@aha_1980 said in Delete a QString From QStringList:

Get used to it, that's the preferred C++ way nowadays ("functional programming").

The major reason for the mortality rise in the developers demographics ... jumping off a tall building ain't no fun ...