str_replace不会替换所有的匹配项，但gsub会吗？

$str = "Hello, world! Hello, everyone!";
$replacement = "Hi";
$new_str = str_replace("Hello", $replacement, $str);
echo $new_str; // 输出 "Hi, world! Hi, everyone!"

str = "Hello, world! Hello, everyone!"
replacement = "Hi"
new_str = str.gsub("Hello", replacement)
puts new_str # 输出 "Hi, world! Hi, everyone!"