Question

I need to improve as much as possible the performance of the function defined below. It is called millions of times, and the <html> <head> <title></title> </head> <body> <?php ini_set('display_errors', 1); error_reporting(~0); $serverName = "localhost"; $userName = "root"; $userPassword = ""; $dbName = "blog_samples"; $conn = mysqli_connect($serverName,$userName,$userPassword,$dbName); $rows_count = count($_POST["name"]); for($i=0;$i<$rows_count;$i++){ // PREVENTING SQL INJECTION !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! $name = mysqli_real_escape_string($conn,$_POST["name"][$i]); $code = mysqli_real_escape_string($conn,$_POST["code"][$i]); $quantity = intval($_POST["quantity"][$i]); $price = mysqli_real_escape_string($conn,$_POST["price"][$i]); $sql = "INSERT INTO order_table (name, code, quantity, price) VALUES ('$name','$code','$quantity','$price')"; $query = mysqli_query($conn,$sql); } if(mysqli_affected_rows($conn)>0) { echo "Record add successfully"; } mysqli_close($conn); ?> </body> </html> loop is currently the bottleneck of my code.

Connection conn = DriverManager.getConnection(Utils.DBURL+"/"+Utils.DBName+"?useUnicode=true&amp;characterEncoding=utf8mb4&amp;", Utils.DBUserName, Utils.DBPassword);

I've tried with:

protected void processRequest(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException{
response.setContentType("application/json");
request.setCharacterEncoding("UTF-8");
String content = request.getParameter("content");
Class.forName("com.mysql.jdbc.Driver");
        Connection conn = 
DriverManager.getConnection(Utils.DBURL+"/"+Utils.DBName+"?
useUnicode=true&amp;characterEncoding=utf8mb4&amp;", Utils.DBUserName, 
Utils.DBPassword);
PreparedStatement stmt = conn.prepareStatement("INSERT INTO "
                            + "`feed`(`content`)"
                            + " VALUES (?)");
stmt.setString(1, content);
stmt.executeUpdate();
}

but it fails with:

for

Answer 1

不是在循环中使用np.random.uniform，而是在一次np.random.random调用中生成足够的随机数，然后适当地缩放它们：

# Could be lows, highs, counts = np.array(d).T, except for the mixed dtypes.
# Taking input as 3 arrays of lows, highs, counts would let you skip this step.
lows, highs, counts = zip(*d) if len(d) else ((), (), ())

base = np.repeat(lows, counts)
scale = np.repeat(highs, counts) - base

random_nums = np.random.random(np.sum(counts)) * scale + base

（除了在循环中调用np.random.uniform之外，减慢原始内容的一个原因是extend带有NumPy数组的列表。这会为数组的每个元素生成包装器对象，缓慢而不必要的过程。）

Fast filling of array with numpy.random.uniform

1 个答案: