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2010-05-25T14:21:17Z

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2010-05-25T10:29:06Z

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==Erase adjacent duplicates==

<source lang="cpp">#include <algorithm>
#include <vector>
#include <string>
#include <iostream>
using namespace std;
typedef vector <string> VECTOR_STRINGS;
int main (){
VECTOR_STRINGS v;
v.push_back ("A");
v.push_back ("B");
v.push_back ("C");
v.push_back ("D");
// insert a duplicate into the vector
v.push_back ("D");
VECTOR_STRINGS::iterator i;
// Erase adjacent duplicates
i = unique (v.begin (), v.end ());
v.erase (i, v.end ());
for (size_t nItem = 0; nItem < v.size (); ++ nItem){
cout << "Name [" << nItem << "] = \"";
cout << v [nItem] << "\"" << endl;
}
return 0;
}</source>

==Erase all value in a vector more than three standard deviations greater than the mean==

<source lang="cpp">#include <algorithm>
#include <cmath>
#include <functional>
#include <iostream>
#include <list>
#include <numeric>
#include <vector>
using namespace std;
template <class T>
void print(T& c){
for( typename T::iterator i = c.begin(); i != c.end(); i++ ){
std::cout << *i << endl;
}
}
int main( )
{
const float a[] = { 1, 1.3, 1.5, 0.9, 0.1, 0.2};
vector<float> data( a,a + sizeof( a ) / sizeof( a[0] ) );
print( data );
float mean = accumulate( data.begin(), data.end(), 0.0f )/ data.size();
vector<float> zero_mean( data );
transform( zero_mean.begin(), zero_mean.end(), zero_mean.begin(),bind2nd( minus<float>(), mean ) );
// compute the sample standard deviation
float deviation = inner_product( zero_mean.begin(),zero_mean.end(), zero_mean.begin(), 0.0f );
deviation = sqrt( deviation / ( data.size() - 1 ) );
// erase all points more than three standard deviations greater than the mean
const int num_deviations = 3;
vector<float>::iterator end = remove_if( data.begin(), data.end(), bind2nd( greater<float>(),mean + num_deviations * deviation ) );
data.erase( end, data.end() );
}</source>

==Erase all value in a vector more than three standard deviations less than the mean with erase() remove_if() and bind2nd==

<source lang="cpp">#include <algorithm>
#include <cmath>
#include <functional>
#include <iostream>
#include <list>
#include <numeric>
#include <vector>
using namespace std;
template <class T>
void print(T& c){
for( typename T::iterator i = c.begin(); i != c.end(); i++ ){
std::cout << *i << endl;
}
}
int main( )
{
const float a[] = { 1, 1.3, 1.5, 0.9, 0.1, 0.2};
// create and initialize vector with above data
vector<float> data( a,a + sizeof( a ) / sizeof( a[0] ) );
cout << "DATA VECTOR HAS " << data.size() << " ELEMENTS\n";
print( data );
// compute the mean
float mean = accumulate( data.begin(), data.end(), 0.0f )/ data.size();
// subtract the mean from every data point
vector<float> zero_mean( data );
transform( zero_mean.begin(), zero_mean.end(), zero_mean.begin(),bind2nd( minus<float>(), mean ) );
// compute the sample standard deviation
float deviation = inner_product( zero_mean.begin(),zero_mean.end(), zero_mean.begin(), 0.0f );
deviation = sqrt( deviation / ( data.size() - 1 ) );
const int num_deviations = 3;
// erase all points more than three standard deviations less than the mean
data.erase( remove_if( data.begin(), data.end(),bind2nd( less<float>(), mean - num_deviations * deviation ) ),data.end() );
}</source>

==Erase first element==

<source lang="cpp">#include <iostream>
using std::cout;
using std::endl;
#include <vector> // vector class-template definition
#include <algorithm> // copy algorithm
#include <iterator> // ostream_iterator iterator
#include <stdexcept> // out_of_range exception
int main()
{
int array[ 6 ] = { 1, 2, 3, 4, 5, 6 };
std::vector< int > integers( array, array + 6 );
std::ostream_iterator< int > output( cout, " " );
integers.push_back( 2 );
integers.push_back( 3 );
integers.push_back( 4 );
cout << "Vector integers contains: ";
std::copy( integers.begin(), integers.end(), output );
// erase first element
integers.erase( integers.begin() );
cout << "\n\nVector integers after erasing first element: ";
std::copy( integers.begin(), integers.end(), output );

return 0;
}</source>
<pre class=codeResult>Vector integers contains: 1 2 3 4 5 6 2 3 4
Vector integers after erasing first element: 2 3 4 5 6 2 3 4</pre>

==erase the numbers 2 through 5 in v1==

<source lang="cpp">#include <vector>
#include <algorithm>
#include <iterator>
#include <iostream>
using namespace std;
void printVector(const vector<int>& v){
copy(v.begin(), v.end(), ostream_iterator<int>(cout, " "));
cout << endl;
}
int main(int argc, char** argv){
vector<int> v1, v2;
int i;
v1.push_back(1);
v1.push_back(2);
v1.push_back(3);
v1.push_back(5);
v1.insert(v1.begin() + 3, 4);
// Add elements 6 through 10 to v2
for (i = 6; i <= 10; i++) {
v2.push_back(i);
}
printVector(v1);
printVector(v2);
// add all the elements from v2 to the end of v1
v1.insert(v1.end(), v2.begin(), v2.end());
printVector(v1);
// erase the numbers 2 through 5 in v1
v1.erase(v1.begin() + 1, v1.begin() + 5);
printVector(v1);
printVector(v2);
return (0);
}</source>

==insert and erase.==

<source lang="cpp">#include <iostream>
#include <vector>
using namespace std;

int main()
{
vector<char> v(10);
vector<char> v2;
char str[] = "<Vector>";
unsigned int i;

for(i=0; i<10; i++) v[i] = i + "a";

// copy characters in str into v2
for(i=0; str[i]; i++)
v2.push_back(str[i]);

// display original contents of vector
cout << "Original contents of v:\n";
for(i=0; i<v.size(); i++) cout << v[i] << " ";
cout << "\n\n";

vector<char>::iterator p = v.begin();
p += 2; // point to 3rd element

// insert 10 X"s into v
v.insert(p, 10, "X");

// display contents after insertion
cout << "Size after inserting X"s = " << v.size() << endl;
cout << "Contents after insert:\n";
for(i=0; i<v.size(); i++) cout << v[i] << " ";
cout << "\n\n";

// remove those elements
p = v.begin();
p += 2; // point to 3rd element
v.erase(p, p+10); // remove next 10 elements

// display contents after deletion
cout << "Size after erase = " << v.size() << endl;
cout << "Contents after erase:\n";
for(i=0; i<v.size(); i++) cout << v[i] << " ";
cout << "\n\n";

// Insert v2 into v
v.insert(p, v2.begin(), v2.end());
cout << "Size after v2"s insertion = ";
cout << v.size() << endl;
cout << "Contents after insert:\n";
for(i=0; i<v.size(); i++) cout << v[i] << " ";
cout << endl;

return 0;
}</source>

==Remove(delete) all elements in the vector==

<source lang="cpp">#include <iostream>
using std::cout;
using std::endl;
#include <vector> // vector class-template definition
#include <algorithm> // copy algorithm
#include <iterator> // ostream_iterator iterator
#include <stdexcept> // out_of_range exception
int main()
{
int array[ 6 ] = { 1, 2, 3, 4, 5, 6 };
std::vector< int > integers( array, array + 6 );
std::ostream_iterator< int > output( cout, " " );
integers.push_back( 2 );
integers.push_back( 3 );
integers.push_back( 4 );
cout << "Vector integers contains: ";
std::copy( integers.begin(), integers.end(), output );
// erase remaining elements
integers.erase( integers.begin(), integers.end() );
cout << "\nAfter erasing all elements, vector integers "
<< ( integers.empty() ? "is" : "is not" ) << " empty";
return 0;
}</source>
<pre class=codeResult>Vector integers contains: 1 2 3 4 5 6 2 3 4
After erasing all elements, vector integers is empty</pre>

==Use unique_copy to remove duplicate words==

<source lang="cpp">/* The following code example is taken from the book
* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/
#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <iterator>
using namespace std;
int main()
{
vector<string> coll;
/* read all words from the standard input
* - source: all strings until end-of-file (or error)
* - destination: coll (inserting)
*/
copy (istream_iterator<string>(cin), // start of source
istream_iterator<string>(), // end of source
back_inserter(coll)); // destination
// sort elements
sort (coll.begin(), coll.end());
/* print all elements without duplicates
* - source: coll
* - destination: standard output (with newline between elements)
*/
unique_copy (coll.begin(), coll.end(), // source
ostream_iterator<string>(cout,"\n")); // destination
}</source>
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