I have a vector of float like:
vector<float> v = [0.4 0.2 0.8 0.1 0.5 0.6];
I would like to create a new vector (call it target):
vector<float> target;
containg only those elements greater than 0.5. I tried this line from this post
copy_if(v.begin(), v.end(), back_inserter(target), bind(less<float>(), 0.5, placeholders::_1));
but when I try to print out the elements in target, I obtain always the first element for n times (with n number of element inside v greater than 0.5).
the print is done in this way:
for (auto i = target.begin(); i != target.end(); ++i) {
cout << target[*i] << endl;
}
Thanks in advance.
In your output, i
is an iterator. target[*i]
will print the element at the position equal to the element at i
's position. Since your values are all less than 1 and greater than 0, *i
always equals 0. This leads to printing the element as position 0 a number of times equal to the number of elements in your vector.
Try the following instead :
for (auto i = target.begin(); i != target.end(); ++i) {
cout << *i << endl;
}
Or simply :
for (auto i : target) {
cout << i << endl;
}
You can use lambda to do it easily
#include <vector>
#include <iostream>
#include <iterator>
#include <algorithm>
using namespace std;
int main()
{
vector<float> v {0.4,0.2,0.8,0.1,0.5,0.6};
vector<float> target;
copy_if(v.begin(), v.end(), back_inserter(target),[](float n ){ return n > 0.5;});
for (auto i = target.begin(); i != target.end(); i++) {
cout << *i << endl;
}
}
Output
0.8
0.6
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