Traversing Arrays

Traversing means accessing each element of an array one by one.

1. Traversing Using for Loop (Indexed Array)

$colors = array("Red", "Green", "Blue");

for($i=0; $i<count($colors); $i++){
   echo $colors[$i];
}

Used When: Index values are known.

2. Traversing Using foreach Loop

Indexed Array

foreach($colors as $color){
   echo $color;
}

Associative Array

$student = array("name"=>"Rohit", "age"=>21);

foreach($student as $key => $value){
   echo $key . " : " . $value;
}

Exam Line: foreach is the most preferred loop for arrays.

3. Traversing Multidimensional Array

foreach($students as $student){
   foreach($student as $value){
      echo $value;
   }
}

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Array Functions in PHP

PHP provides many built-in functions to work with arrays.

Commonly Used Array Functions

1. count()

Returns number of elements.

echo count($colors);

2. sort()

Sorts array in ascending order.

sort($colors);

3. rsort()

Sorts array in descending order.

rsort($colors);

4. array_push()

Adds element at the end.

array_push($colors, "Yellow");

5. array_pop()

Removes last element.

array_pop($colors);

6. array_merge()

Merges two arrays.

$result = array_merge($a1, $a2);

7. in_array()

Checks if value exists.

if(in_array("Red", $colors)){
   echo "Found";
}

8. array_key_exists()

Checks if key exists.

array_key_exists("name", $student);

9. explode()

Converts string to array.

$arr = explode(",", "Red,Green,Blue");

10. implode()

Converts array to string.

$str = implode("-", $colors);

Summary Table of Array Functions

Exam Tip: Array functions reduce code length and improve efficiency.

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Advantages of Arrays

• Store multiple values
• Easy data management
• Efficient looping
• Useful for database operations