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<?php function is_natural($val) { $val = (string)$val; return (bool)ctype_digit($val) && $val === (string)(int)$val && $val > 0; } var_dump(is_natural(15)); // true var_dump(is_natural(0)); // false var_dump(is_natural(-1)); // false var_dump(is_natural('5')); // true var_dump(is_natural('01')); // false var_dump(is_natural('1.5')); // false var_dump(is_natural('0x18')); // false
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.1 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.25, 7.0.0 - 7.0.20, 7.1.0 - 7.1.20, 7.2.6 - 7.2.33, 7.3.12 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
bool(true) bool(false) bool(false) bool(true) bool(false) bool(false) bool(false)
Output for 5.1.0
Fatal error: fatal flex scanner internal error--end of buffer missed in /in/DHWR9 on line 12
Process exited with code 255.
preferences:
264.56 ms | 401 KiB | 353 Q