Get the length of a string - strlen()

                
                    <?php
                    echo strlen("Hello world!");
                    ?>
                
                

Count the number of words in a string - str_word_count()

                
                    <?php
                    echo str_word_count("Hello world!");
                    ?>
                
                

Reverse a string - strrev()

                
                    <?php
                    echo strrev("Hello world!");
                    ?>
                
                

Search for a specific text within a string - strpos()

                
                    <?php
                    echo strpos("Hello world!", "world");
                    ?>
                
                

Replace text within a string - str_replace()

                
                    <?php
                    echo str_replace("world", "Dolly", "Hello world!");
                    ?>