PHP 验证数字是否有效
示例
将值验证为float，并在成功时转换为float。
var_dump(filter_var(1, FILTER_VALIDATE_FLOAT));
var_dump(filter_var(1.0, FILTER_VALIDATE_FLOAT));
var_dump(filter_var(1.0000, FILTER_VALIDATE_FLOAT));
var_dump(filter_var(1.00001, FILTER_VALIDATE_FLOAT));
var_dump(filter_var('1', FILTER_VALIDATE_FLOAT));
var_dump(filter_var('1.0', FILTER_VALIDATE_FLOAT));
var_dump(filter_var('1.0000', FILTER_VALIDATE_FLOAT));
var_dump(filter_var('1.00001', FILTER_VALIDATE_FLOAT));
var_dump(filter_var('1,000', FILTER_VALIDATE_FLOAT));
var_dump(filter_var('1,000.0', FILTER_VALIDATE_FLOAT));
var_dump(filter_var('1,000.0000', FILTER_VALIDATE_FLOAT));
var_dump(filter_var('1,000.00001', FILTER_VALIDATE_FLOAT));
var_dump(filter_var(1, FILTER_VALIDATE_FLOAT, FILTER_FLAG_ALLOW_THOUSAND));
var_dump(filter_var(1.0, FILTER_VALIDATE_FLOAT, FILTER_FLAG_ALLOW_THOUSAND));
var_dump(filter_var(1.0000, FILTER_VALIDATE_FLOAT, FILTER_FLAG_ALLOW_THOUSAND));
var_dump(filter_var(1.00001, FILTER_VALIDATE_FLOAT, FILTER_FLAG_ALLOW_THOUSAND));
var_dump(filter_var('1', FILTER_VALIDATE_FLOAT, FILTER_FLAG_ALLOW_THOUSAND));
var_dump(filter_var('1.0', FILTER_VALIDATE_FLOAT, FILTER_FLAG_ALLOW_THOUSAND));
var_dump(filter_var('1.0000', FILTER_VALIDATE_FLOAT, FILTER_FLAG_ALLOW_THOUSAND));
var_dump(filter_var('1.00001', FILTER_VALIDATE_FLOAT, FILTER_FLAG_ALLOW_THOUSAND));
var_dump(filter_var('1,000', FILTER_VALIDATE_FLOAT, FILTER_FLAG_ALLOW_THOUSAND));
var_dump(filter_var('1,000.0', FILTER_VALIDATE_FLOAT, FILTER_FLAG_ALLOW_THOUSAND));
var_dump(filter_var('1,000.0000', FILTER_VALIDATE_FLOAT, FILTER_FLAG_ALLOW_THOUSAND));
var_dump(filter_var('1,000.00001', FILTER_VALIDATE_FLOAT, FILTER_FLAG_ALLOW_THOUSAND));结果
float(1) float(1) float(1) float(1.00001) float(1) float(1) float(1) float(1.00001) bool(false) bool(false) bool(false) bool(false) float(1) float(1) float(1) float(1.00001) float(1) float(1) float(1) float(1.00001) float(1000) float(1000) float(1000) float(1000.00001)