How to Filter Elements of a List based on a Condition in C++

How to Filter Elements of a List based on a Condition in C++ ?

Answer

To filter elements of a list based on a condition in C++, you can use the remove_if algorithm along with a lambda expression.

✐ Examples

1 Filter Integers Greater Than a Threshold

In this example,

We create a list named numbers with integer values.
We use the remove_if algorithm along with a lambda expression to remove elements that do not satisfy the condition.
We use the erase method to erase the removed elements.
Finally, we print the filtered list to standard output.

C++ Program

#include <iostream>
#include <list>
#include <algorithm>

int main() {
    std::list<int> numbers = {1, 2, 3, 4, 5};
    int threshold = 3;
    numbers.remove_if([&threshold](int num) { return num <= threshold; });
    for (int num : numbers) {
        std::cout << num << " ";
    }
    return 0;
}

Output

4 5

2 Filter Strings Containing a Substring

In this example,

We create a list named words with string values.
We use the remove_if algorithm along with a lambda expression to remove elements that do not satisfy the condition.
We use the erase method to erase the removed elements.
Finally, we print the filtered list to standard output.

C++ Program

#include <iostream>
#include <list>
#include <algorithm>
#include <string>

int main() {
    std::list<std::string> words = {"apple", "banana", "cherry", "date", "elderberry"};
    std::string substring = "erry";
    words.remove_if([&substring](const std::string& word) { return word.find(substring) == std::string::npos; });
    for (const std::string& word : words) {
        std::cout << word << " ";
    }
    return 0;
}

Output

cherry elderberry

Summary

In this tutorial, we learned How to Filter Elements of a List based on a Condition in C++ language with well detailed examples.

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How to Filter Elements of a List based on a Condition in C++

How to Filter Elements of a List based on a Condition in C++ ?

Answer

✐ Examples

1 Filter Integers Greater Than a Threshold

C++ Program

Output

2 Filter Strings Containing a Substring

C++ Program

Output

Summary

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