PHP Basics (ii) 1, random number and time 2, String function

One, random number and time
Random number generator (JS:math.random)
echo rand ();

Generate a random number in a range
echo rand (0,10);

Time stamp
echo Time ();

Format the display of time
echo "<br>";
echo Date ("Y-m-d h:i:s", Time ());
echo "<br>";
echo Date ("Y-m-d h:i:s", "101506494366");

Convert String to Timestamp
echo "<br>";
Echo strtotime ("2017-09-27 14:49:13");


echo "<br>";

Second, String function
Length  Str.length
$str 1 = "ABCDEFG";
$str 2 = "ABCD";
Echo strlen ($str 1);
Comparison of two string lengths
echo "<br>";
Var_dump (strcmp ($str 1, $str 2));

Turn lowercase
echo "<br>";
Echo strtolower ("ABCDE");

Turn capital
echo "<br>";
Strtoupper ();

Splits a string, returns an array
echo "<br>";
Var_dump (Explode ("B", $str 2));

Stitching array elements into a single string
echo "<br>";
echo Implode ("|", ["a", "B", "C"]);

Find replacements
echo "<br>";
Echo str_replace ("CD", "CD", $str 1);

Replace the specified position character
echo "<br>";
Echo Substr_replace ($str 1, "xxx", 0, 3);

Intercept string
echo "<br>";
Echo substr ($str 1,1,3);

PHP Basics (ii) 1, random number and time 2, String function