interview

Find a word in a string and replace it.?

<?php
$string = "Array99 has good blog for PHP programming.";
$newString = str_replace("good", "nice", $string);
echo $newString;    //Output: Array99 has nice blog for PHP programming."
?>

3. Find a position of a word in a string.
Ans: 
<?php
$string = "Array99 has good blog for PHP programming.";
$pos = strpos($string, "good");
echo $pos; //Output: 12
?>

4. How to display first 100 characters of a paragraph.
Ans: 

<?php

$paragraph = "OOPs is a powerful software development concept and it always insists to minimize, reuse and better management of code. Inheritance is one of the powerful features of OOPs which provides re-usability of code. Traits which is a new feature introduce in PHP 5.4. The concept of traits added some extra feature in single inheritance.";

$substring = substr($paragraph, 0, 100);

echo $substring;

//Output: OOPs is a powerful software development concept and it always insists to minimize, reuse and better

?>

5. Find last 4 letter of the string.
Ans: 

<?php

$string = "Array99 has good blog for PHP programming";

$substring = substr($string, -4);

echo $substring; //Output: ming

?>

6. Extract “good blog” from of below string.
Array99 has good blog for PHP programming.
Ans:

<?php

$string = "Array99 has good blog for PHP programming.";

$extractWord = "good blog";

$substring = substr($string, strpos($string, $extractWord), strlen($extractWord));

//echo strpos($string, $extractWord);//o/p= 12 // in numbering order 12 position goog blog starts

echo $substring; //Output: good blog

?>

7. Find the index of any element in an array.
Ans:

<?php

$numbers = array(5, 3, 7, 9, 6, 8);

echo array_search(7, $numbers);
//Output: 2

?>

7. What will be output of below code and why?
<?php
$string = "Array99 has good blog for PHP programming.";
$substr = "Array99";
if(strpos($string, $substr))
{
                echo "found";
}
else
{
                echo "not found";
}
?>
Ans:
Output will be “not found” because strpos($string, $substr) returns 0 as position and this is treated as false in IF condition.So the right code below.
<?php
$string = "Array99 has good blog for PHP programming.";
$substr = "Array99";
if(strpos($string, $substr) !== false)
{
                echo "found";
}
else
{
                echo "not found";
}
?>

8. How to remove first two elements from an array.
Ans:

<?php

$alphabats = array("a", "b", "c", "d", "e");

$output = array_slice($alphabats, 2);

print_r($output);

//Output Array ( [0] => c [1] => d [2] => e )

?>

9. How to remove two elements from middle in below array.
$colors = array("red", "green", "blue", "yellow");
Ans:

<?php

$colors = array("red", "green", "blue", "yellow");

array_splice($colors, 1, -1);

print_r($colors);

//Output: Array ( [0] => red [1] => yellow )

?>

10. How to remove last element and insert two new elements in below array.
$colors = array("red", "green", "blue", "yellow");
$lastColors = array("orange", "maroon");
Ans:

<?php

$colors = array("red", "green", "blue", "yellow");

array_splice($colors, -1, 1, $lastColors);

print_r($colors);

//Output: Array ( [0] => red [1] => green [2] => blue [3] => orange [4] => maroon )

?>

11. Check element in below array is an array or not.
Ans:
<?php
$colors = array("red", "green", array("orange", "maroon"), "blue", "yellow", array("purple", "brown"));
foreach($colors as $c)
{
    if(is_array($c))
    {
        echo "This element is an array.";
    }
    else
    {
        echo "This element is not an array.";
    }
}
?>

12. Convert any name in an array.
Ans:

<?php

$name = "sachin tendulkar";

$nameArray = array();

for($i = 0; $i<strlen($name); $i++)

{

    $nameArray[] = $name[$i]; 

}

print_r($nameArray);

//Output: Array ( [0] => s [1] => a [2] => c [3] => h [4] => i [5] => n [6] => [7] => t [8] => e [9] => n [10] => d [11] => u [12] => l [13] => k [14] => a [15] => r )

?>

13. Find the 2nd last salary. What will happen when two salaries are same in MySql?
Ans:  Suppose you have an employee table

SELECT * FROM employee ORDER BY salary DESC LIMIT 1, 1
 But the above query will be fail same salary occurs multiple times in table. 

+----+---------+--------+
| id | name    | salary |
+----+---------+--------+
|  1 | Sachin  |  20000 |
|  2 | William |  25000 |
|  3 | Tom     |  20000 |
|  4 | Anky    |  25000 |
+----+---------+--------+

So below is the right query:

SELECT * FROM employee GROUP BY salary ORDER BY salary DESC LIMIT 1, 1

14. Write a query to find all students who have taken admission in before 1 month from “students” table.
Ans: 
SELECT * FROM `students` WHERE admission_date <= date_sub(curdate(), INTERVAL 1 month);

15. Write a query to find all coming payments from “payments” table.
Ans:

SELECT * FROM `payments` WHERE payment_date >= curdate();  

16. Write a query to find all customers who have purchasing amount in greater than 1000.
Ans:

+----+---------------+--------------+
| id | customer_name | purchase_amt |
+----+---------------+--------------+
|  1 | Sachin        |          500 |
|  2 | William       |          800 |
|  3 | William       |          400 |
|  4 | William       |          700 |
|  5 | Sachin        |          100 |
+----+---------------+--------------+

SELECT customer_name, SUM(purchase_amt) FROM `customers_orders` GROUP BY customer_name HAVING SUM(purchase_amt) > 1000;

17. Write a select query for below table so that F should display as FEMALE and M should display as MALE for gender field. 
Ans:

+----+---------------+--------------+--------+
| id | customer_name | purchase_amt | gender |
+----+---------------+--------------+--------+
|  1 | Soha          |          500 | F      |
|  2 | William       |          800 | M      |
|  3 | Honey         |          400 | F      |
|  4 | Tom           |          700 | M      |
|  5 | Sachin        |          100 | M      |
+----+---------------+--------------+--------+
SELECT customer_name, purchase_amt, (CASE WHEN gender = 'F' THEN 'FEMALE' WHEN gender = 'M' THEN 'MALE' END) AS gender FROM `customers_orders`;

18. Write a select query to implement SELF JOIN.
Ans:

+----+------------+---------+
| id | reports_to | name    |
+----+------------+---------+
|  1 |          0 | Sachin  |
|  2 |          0 | William |
|  3 |          2 | Tom     |
|  4 |          1 | Anky    |
|  5 |          1 | Mona    |
|  6 |          3 | Vincy   |
+----+------------+---------+

SELECT 

    e1.name AS 'Manager',
    e2.name AS 'Report To'

FROM

    employee e1
        INNER JOIN
    employee e2 ON e2.id = e1.reports_to
ORDER BY e1.id DESC 

Below, there are some patterns related to star, number and alphabets that are also asked in interview to test your logic. Some below: 

19. Write a program to display below pattern.

*
* *
* * *
* * * *
* * * * *

Ans: 
 <?php
for($i = 1;$i<=5;$i++){
    for($j=1;$j<=$i;$j++){
        echo "*";
    }
    echo "<br>";
}
?>

20. Write a program to display below pattern.

* * * * *
* * * *
* * *
* *
*

Ans:
<?php
for($i = 5;$i>=1;$i--){
    for($j=0;$j<$i;$j++){
        echo "*";
    }
    echo "<br>";
}
?>

 21. Write a program to display below pattern.

1
2 2
3 3 3
4 4 4 4
5 5 5 5 5

Ans:
<?php
for($i = 1;$i<=5;$i++){
    for($j=1;$j<=$i;$j++){
        echo $i;
    }
    echo "<br>";
}
?>

22. Write a program to display below pattern.

1
2 3
4 5 6
7 8 9 10

Ans:
<?php
$k = 1;
for($i = 1; $i<=4; $i++){
    for($j=1; $j<=$i; $j++){
        echo $k;
        $k++;
    }
    echo "<br>";
}
?>

5. Write a program to display below pattern.

      1
    1 2 1
  1 2 3 2 1
1 2 3 4 3 2 1

Ans:
<?php
for($i = 1; $i<=4; $i++){
    for($j=4; $j>=$i; $j--){
        echo "&nbsp;&nbsp;";
    }
    for($k=1; $k<=$i; $k++){
        echo $k;
    }
    for($m=($i-1); $m>=1; $m--){
        echo $m;
    }
    echo "<br>";
}
?>

6. Write a program to display below pattern.

   *
  ***
 *****
*******

Ans:
<?php
for($i = 1; $i<=4; $i++){
    for($j=4; $j>=($i + 1); $j--){
        echo "&nbsp;&nbsp;";
    }
    for($k=1; $k<=$i; $k++){
        echo "*";
    }
    for($m=2; $m<=$i; $m++){
        echo "*";
    }
    echo "<br>";
}
?>