erase-remove-idiom

Ok, I expect I've made a dumb mistake here. I have a list of DisplayDevice3d and each DisplayDevice3d contains a list of DisplayMode3d. I want to remove all items from the list of DisplayDevice3d that don't have any DisplayMode3d's. I'm trying to use a Lambda to do it, ie.: // If the device doesn't have any modes, remove it. std::remove_if(MyDisplayDevices.begin(), MyDisplayDevices.end(), [](DisplayDevice3d& device) { return device.Modes.size() == 0; } ); Even though out of 6 DisplayMode3d's in MyDisplayDevices, only 1 has any DisplayMode3d's in its Modes collection, nothing is being removed

I've created a function to run through a vector of strings and remove any strings of length 3 or less. This is a lesson in using the STL Algorithm library. I'm having trouble in that the functions work but not only does it delete strings of length 3 or less but it also appends the string "vector" to the end. The output should be This test vector and instead it is This test vector vector" How can I fix it? /* * using remove_if and custom call back function, write RemoveShortWords * that accepts a vector<string> and removes all strings of length 3 or * less from it. *shoot for 2 lines of code in

The task of removing elements with a certain property from a std::vector or other container lends itself to a functional style implementation: Why bother with loops, memory deallocation and moving data around correctly? However the standard way of doing this in C++ seems to be the following idiom: std::vector<int> ints; ... ints.erase( std::remove_if(ints.begin(), ints.end(), [](int x){return x < 0;}), ints.end()); This example removes all elements less than zero from an integer vector. I find it not only ugly but also easy to use incorrectly. It is clear that std::remove_if cannot change the

Let's say I have std::vector<std::pair<int,Direction>> . I am trying to use erase-remove_if idiom to remove pairs from the vector. stopPoints.erase(std::remove_if(stopPoints.begin(), stopPoints.end(), [&](const stopPointPair stopPoint)-> bool { return stopPoint.first == 4; })); I want to delete all pairs that have .first value set to 4. In my example I have pairs: - 4, Up - 4, Down - 2, Up - 6, Up However, after I execute erase-remove_if, I am left with: - 2, Up - 6, Up - 6, Up What am I doing wrong here? The correct code is: stopPoints.erase(std::remove_if(stopPoints.begin(), stopPoints.end()

This question already has an answer here: How do I remove an item from a stl vector with a certain value? 10 answers vector<int> myVector; and lets say the values in the vector are this (in this order): 5 9 2 8 0 7 If I wanted to erase the element that contains the value of "8", I think I would do this: myVector.erase(myVector.begin()+4); Because that would erase the 4th element. But is there any way to erase an element based off of the value "8"? Like: myVector.eraseElementWhoseValueIs(8); Or do I simply just need to iterate through all the vector elements and test their values? Georg