PHP Mobile Internet Development Notes (5) - Basic Function Library_PHP Tutorial

1. Math function library

● floor

Round to the nearest whole number (Round down)

float floor (float $value);

<?php
echo(floor(0.60)."<br>");
echo(floor(0.40)."<br>");
echo(floor(5)."<br>");
echo(floor(5.1)."<br>");
echo(floor(-5.1)."<br>");
echo(floor(-5.9)."<br>")
?>

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● ceil

Round up (round up)

float ceil(float $value);

<?php
echo(ceil(0.60)."<br>");
echo(ceil(0.40)."<br>");
echo(ceil(5)."<br>");
echo(ceil(5.1)."<br>");
echo(ceil(-5.1)."<br>");
echo(ceil(-5.9)."<br>")
?>

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● max

Take the maximum value

mixed max(mixed $value, mixed $value, ...);

<?php
echo(max(5,7)."<br>");
echo(max(-3,5)."<br>");
echo(max(-3,-5)."<br>");
echo(max(7.25,7.30)."<br>");
?>

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● min

Take the minimum value

mixed min(mixed $value, mixed $value, ...);

<?php
echo(min(5,7)."<br>");
echo(min(-3,5)."<br>");
echo(min(-3,-5)."<br>");
echo(min(7.25,7.30)."<br>");
?>

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● pow

Power operation

number pow(number $base, number $expr);

<?php
echo pow(4,2)."<br>";
echo pow(6,2)."<br>";
echo pow(-6,2)."<br>";
echo pow(-6,-2)."<br>";
echo pow(-6,5.5)."<br>";
?>

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● sqrt

Take the square root

float sqrt(float $arg)

<?php
echo(sqrt(0))."<br>";
echo(sqrt(1))."<br>";
echo(sqrt(9))."<br>";
echo(sqrt(0.64))."<br>";
echo(sqrt(-9))."<br>";
?>

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● rand

Generate random numbers

int mt_rand(int $min, int max);

<?php
echo rand()."<br>";
echo rand(10,100)."<br>";
?>

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● mt_rand

Produces a better random number

int mt_rand(int $min, int max);

Similar to the rand usage and output results above, this is 4 times faster than rand.

● round

Round

float round(float $val [, int $precision =0])

The second parameter is optional, specifying the number of decimal places to retain

● number_format

Format number by thousands grouping

float number_format(float $number, int $decimals=0, string $dec_point=",', string $thousands_sep=',');

● time

Returns the current Unix timestamp

int time(void);

<?php
echo time()."<br>";
$nextWeek = time() + (7 * 24 * 60 * 60); // 7 days; 24 hours; 60 mins; 60secs
echo 'Now:       '. date('Y-m-d') ."<br>";
echo 'Next Week: '. date('Y-m-d', $nextWeek) ."<br>";
?>

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● date

Format a local time/date

string date(string format[, int timestamp]);

● getdate

Get date /Time information

array getdate([int timestamp]);

<?php
print_r(getdate());
?>

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MD5 ha Hope

string md5(string $str[, bool $raw_output=false]);

strpos

Returns the position of the first occurrence of one character in another character

int strpos(string haystack, mixed needle[, int offset]);