PHP Echo, print, printf, sprintf function differences and use

1. Echo Function:

The output function , which is a command, cannot return a value. Echo can be followed by a number of parameters, separated by semicolons, such as: Echo $myvar 1; Echo, $myvar, "<b>bold</b>";

2. print Function:

is a function that returns a value that can have only one parameter.

int print (string arg)

Outputs arg . Returns 1 , always.

3. printf function:

int printf (string format [, mixed args [, mixed ...]) )

Produces output according format to, which are described in the documentation for sprintf () .

Returns the length of the outputted string.

The text formatted after the output, such as: $name = "Hunte"; $age = 25; printf ("My name is%s, age%d", $name, $age);

4. sprintf function:

String sprintf (string format [, mixed args [, mixed ...])

Returns a string produced according to the formatting string format .

Similar to printf, but does not print, but returns formatted text, the rest is the same as printf.

5. The printf () function is explained in detail:

The printf () function is called in the format: printf ("< formatted string >", < Parameter table >);

%d decimal signed integer%u decimal unsigned integer%f floating-point number%s string%c single character%p pointer value%e exponential floating point%x,%x unsigned integer in hexadecimal%o unsigned integer%g in octal to automatically select an appropriate representation

Description:

(1). You can insert a number between "%" and a letter to indicate the maximum field width.

① For example:%3d represents the output of 3-bit integers, not enough 3-bit right-justified.

The ②%9.2f represents a floating-point number with an output field width of 9, where the decimal bit is 2, the integer digit is 6, the decimal point is one, and not enough 9-bit right-aligned.

The ③%8s represents the output of a 8-character string, which is not aligns aligned to 8 characters.

④ if the length of the string or the number of integers exceeds the width of the description, the output is based on its actual length.

⑤ floating point number, if the integer number of bits exceeds the width of the indicated integer digits, the actual integer digits will be output;

⑥ fractional digits exceed the indicated decimal width, the output is rounded by the width of the description.

⑦ If you want to add some 0 before the output value, add a 0 before the field width.

For example,%04d means that when you output a value that is less than 4 bits, it will be preceded by 0 to make its total width 4 bits.

⑧ If you use floating-point numbers to represent the output format of a character or integer, the number after the decimal point represents the maximum width, and the number before the decimal point represents the minimum width.

For example,%6.9s indicates that a string with a length of not less than 6 and not greater than 9 is displayed. If it is greater than 9, the contents of the 9th character will be deleted.

(2). You can add a lowercase letter L between "%" and the letter, indicating that the output is a long form.

① For example:%ld indicates an output long integer

②%LF indicates the output double floating-point number

(3). You can control the output left or right alignment, that is, "%" and the letter by adding a "-" sign to indicate that the output is left-justified, otherwise it is right-justified.

① For example:%-7d indicates output 7-bit integer left justified

②%-10s indicates output 10 characters aligns aligned

(4). Some special provisions of the character

①\n line ②\f Clear screen and change page ③\r carriage return ④\t tab character ⑤\XHH represents an ASCII code with 16-in notation, ⑥ where HH is 1 to 2 16 decimal

6. printf () : examples

Example 1: various examples

<?php $n = 43951789;  $u =-43951789; $c = 65; ASCII is ' A '//notice the double percent, this prints A literal '% ' character printf ("%%b = '%b ' \ n", $n); Binary representation printf ("%%c = '%c ' \ n", $c); Print the ASCII character, same as Chr () function printf ("%%d = '%d ' \ n", $n); Standard integer Representation printf ("%%e = '%e ' \ n", $n); Scientific notation printf ("%%u = '%u ' \ n", $n); unsigned integer representation of a positive integer printf ("%%u = '%u ' \ n", $u); unsigned integer representation of a negative integer printf ("%%f = '%f ' \ n", $n); Floating point representation printf ("%%o = '%o ' \ n", $n); Octal representation printf ("%%s = '%s ' \ n", $n); String representation printf ("%%x = '%x ' \ n", $n); Hexadecimal representation (lower-case) printf ("%%x = '%x ' \ n", $n); Hexadecimal representation (upper-case) printf ("%%+d = '%+d ' \ n", $n); Sign specifier on a positive integer printf ("%%+d = '%+d ' \ n", $u); Sign specifier on a Negative integer?> The printout of this program would be:%b = ' 10100111101010011010101101 '%c = ' A '%d = ' 43951789 '%e = ' 4.39518e+7 '%u = ' 43951789 '%u = ' 4251015507 '%f = ' 43951789.000000 '%o = ' 247523255 '%s = ' 43951789 '%x =   ' 29ea6ad '%x = ' 29ea6ad '%+d = ' +43951789 '%+d = '-43951789 '

Example 2: string Specifiers

<?php$s = ' monkey ';  $t = ' many monkeys ';     printf ("[%s]\n",      $s);//Standard string output  printf ("[%10s]\n",    $s);//right-justification with spaces  printf ("[%-10s]\n",   $s);//left-justification with spaces  printf ("[%010s]\n",   $s);// Zero-padding works on strings too  printf ("[% ' #10s]\n",  $s);//Use the custom padding character ' # '  printf ("[%10.10s]\n", $t); Left-justification but with a cutoff of ten characters?> the printout of this program       would be:   [monk EY]  [    monkey] [  monkey    ]  [0000monkey]  [# # #monkey]  [many Monke]  

Example 3:zero-padded integers

<?php  $isodate = sprintf ("%04d-%02d-%02d", $year, $month, $day);  ? >   

Example 4:formatting currency

<?php  $money 1 = 68.75;  $money 2 = 54.35;  $money = $money 1 + $money 2;  echo $money would output "123.1";  $formatted = sprintf ("%01.2f", $money);  echo $formatted would output "123.10"  ?>   

Example 5: sprintf () : Scientific notation

<?php  $number = 362525200;  Echo sprintf ("%.3e", $number); Outputs 3.63e+8  ?>   

PHP Echo, print, printf, sprintf function differences and use