How to check an existance of a chart?

[firsnur96]

How can i check the existance of chart_olstr[0] for removing the series.
Because if chart_olstr[0] is not exist my app crash

      ```
      chart_olstr[0]->removeSeries(seri[i]);
      chart_olstr[0]->legend()->hide();
      chart_olstr[0]->update();
      seri[i]->clear();

[JonB]

@firsnur96 said in How to check an existance of a chart?:

Because if chart_olstr[0] is not exist my app crash

Is chart_olstr an array or list or whatever? So check its length/count or whether it is empty before attempting to address element #0 in it....

[firsnur96]

@JonB yes it is an array.
I cannot found any function like isEmpy, how should i check its lenght

[JonB]

@firsnur96
Look at the documentation for whatever actual type you mean by "array".

If it is a C-array, it won't have any varying length/count. But then you know its size/what elements you put in, or you are maintaining your own count variable.

[Pl45m4]

@firsnur96

What kind of array? QVector? QList?
What about chart_olstr.size()?

Or just check element 0:
chart_olstr[0] != nullptr