display-statements.md

➲ Display Statements:

PHP offers different ways to display output data to the browser.

☴ Overview:

1. Echo Statement
2. Print Statement
3. Multi-line Printing
4. Printf Function
5. Sprintf Function
6. Print_r Function
7. Var_dump Function
8. Vprintf Function
9. Vsprintf Function
10. Comparison Among Statements

✦ Echo Statement:

It is most common and one of the display and output statement in PHP. It efficient than any other display statements.

Syntax:

echo expression1, expression2, ...;

Explanation:

• It prints one or more expressions.
• It doesn't return a value.
• It can be used without parentheses.

Example:

echo "Welcome, user! ", "to the page";
echo "<p>This is a paragraph.</p>";

✦ Print Statement:

It is most common and one of display and output statement in PHP.

Syntax:

print expression;

Explanation:

• It prints a single expression only.
• It returns 1 on success, 0 on failure.
• It requires parentheses sometimes.

Example:

print("Welcome, user!");
print "<p>This is a paragraph.</p>";

✦ Multi-line Printing:

To print multiple lines, use either print or echo with newlines:

Example:

echo "Line 1\nLine 2\nLine 3";

Example: use nl2br() to convert newlines to <br> tags:

echo nl2br("Line 1\nLine 2\nLine 3");

✦ Printf Function:

The printf() function in PHP is used to format and print strings. It accepts a format string as the first argument and additional arguments as the subsequent parameters. The format string contains format specifiers that act as a placeholder that are replaced with the corresponding arguments.

Syntax:

printf(format_string, argument1, argument2, ...);

Explanation:

• It formats output using placeholders in the format string.

• Format specifiers:

  Specifier	Description	Example
  %s	String	printf("Name: %s", "Kumar")
  %d	Integer	printf("Age: %d", 30)
  %f	Floating-point number	printf("Pi: %.2f", 3.14159)
  %e	Scientific notation	printf("Avogadro's number: %e", 6.02214076e23)
  %x	Hexadecimal number (lowercase)	printf("Hexadecimal: %x", 255)
  %X	Hexadecimal number (uppercase)	printf("Hexadecimal: %X", 255)
  %o	Octal number	printf("Octal: %o", 255)
  %b	Binary number	printf("Binary: %b", 255)
  %%	Literal percent sign	printf("Percentage: %%")

• Additional Formatting Options:

  • Precision: Specify the number of decimal places for float numbers:

  printf("Pi: %.3f", 3.14159); // Output: Pi: 3.142

  • Zero-padding: Use the 0 flag:

  printf("Visits: %010d", 30); // Output: Visits: 000000030

Example:

$name = "Kumar";
$age = 30;
printf("Name: %s, Age: %d\n", $name, $age);

$price = 36.89;
$hex = 0xFF;
$binary = 1010;

printf("Price: %.2f\nHex: %x\nBinary: %b\n", $price, $hex, $binary);

✦ Sprintf Function:

It similar to printf() function, but returns the formatted string instead of printing it directly.

Syntax:

$formatted_string = sprintf(format_string, argument1, argument2, ...);

Example:

$name = "Kumar";
$age = 30;
$formatted_string = sprintf("Name: %s, Age: %d\n", $name, $age);
echo $formatted_string;

✦ Print_r Function:

It prints human-readable information about a variable. For debugging and inspecting complex data structures.

Syntax:

print_r(expression, boolean);

Explanation:

• It accepts optional second argument boolean to controls the output format:
  • true: Returns the output as a string.
  • false (default): Prints the output directly.

Example:

$array = [1, 2, 3];
print_r($array);

echo print_r($array, true);

✦ Var_dump Function:

It prints detailed information about one or more expressions, including their type and value. And it is useful for debugging.

Syntax:

var_dump(expression1, expression2, ...);

Example:

$array = [1, 2, 3];
var_dump($array);

✦ Vprintf Function:

It is similar to printf function, but uses an array of arguments instead of number of variable arguments.

✦ Vsprintf Function:

It is similar to sprintf function, but accepts array of arguments.

✦ Comparison Among Statements:

Function	Description	Return Value	Use Cases
echo	Outputs one or more strings	None	Simple output, printing HTML content
print	Outputs a single string	1 on success, 0 on failure	Similar to echo, but can be used in one expression at a time
printf	Formats output using placeholders	None	Formatting output with specific data types (e.g., numbers, strings)
sprintf	Similar to printf, but returns the formatted string instead of printing it	Formatted string	Storing formatted strings for later use
vprintf	Like printf, but takes an array of arguments	None	Formatting output with number of arguments as a variable
vsprintf	Like sprintf, but takes an array of arguments and returns the formatted string	Formatted string	Storing formatted strings with a variable number of arguments
print_r	Prints human-readable information about a variable	None	Debugging and inspecting complex data structures (arrays, objects)
var_dump	Dumps information about a variable, including its type and value	None	Debugging and inspecting variables in detail

Choosing the Right Function:

• Return Value: print returns 1 on success, while echo doesn't return anything.
• Argument Count: echo can take multiple arguments, while print takes only one.
• Formatting: printf and sprintf offer more control over formatting output using placeholders.
• Debugging: print_r and var_dump are useful for debugging and inspecting complex data structures.

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