PHP 在 while 循环中 echo 问题

发布于 2024-09-07 20:07:16 字数 558 浏览 7 评论 0原文

我使用 while 循环读取 csv 文件:

while (($data = fgetcsv($handle, null, ",")) !== FALSE) 

并且我想跳过第一行,因为这是标题行,我想在屏幕上显示“跳过第一行”。

if($data[0]=="title")
echo "Title row..skipping<br />";  
else
//do stuff

问题是因为它在一个 while 循环中,所以它多次打印出“标题行...跳过”,如下所示:

Checking row 0...
Title row..skipping
Title row..skipping
Title row..skipping
Title row..skipping
Title row..skipping
Title row..skipping
Title row..skipping
Checking row 1...

我应该做什么,这样它只打印一次?这和php的输出缓冲有什么关系吗?

I read in a csv file by using a while loop:

while (($data = fgetcsv($handle, null, ",")) !== FALSE) 

and i want to skip the first row because this is the title row and i want to display on the screen "first line skipped".

if($data[0]=="title")
echo "Title row..skipping<br />";  
else
//do stuff

The problem is since its in a while loop it prints out "Title row...skipping" a bunch of times shown here:

Checking row 0...
Title row..skipping
Title row..skipping
Title row..skipping
Title row..skipping
Title row..skipping
Title row..skipping
Title row..skipping
Checking row 1...

what should i do so it only prints it out once? does it have something to do with php's output buffering?

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评论(4

み青杉依旧 2024-09-14 20:07:16

或者在不进行赋值的情况下调用一次 fgetcsv($handle, null, ",") ,将处理程序向前移动一行:

fgetcsv($handle, null, ",");

while (($data = fgetcsv($handle, null, ",")) !== FALSE) {
    // do stuff
}

Or call fgetcsv($handle, null, ",") once without assignment, to move the handler forward by one line:

fgetcsv($handle, null, ",");

while (($data = fgetcsv($handle, null, ",")) !== FALSE) {
    // do stuff
}
迟月 2024-09-14 20:07:16
if($data[0]=="title") {
  if (!$skipped) {
    echo "Title row..skipping<br />";
    $skipped = true;
  }
}
else
//do stuff
if($data[0]=="title") {
  if (!$skipped) {
    echo "Title row..skipping<br />";
    $skipped = true;
  }
}
else
//do stuff
烟花易冷人易散 2024-09-14 20:07:16

如果您确定只需要跳过第一行;

if(!$skipped)
{
    echo "Title row..skipping<br />";
    $skipped = true;
}
else
//do stuff

If you know for a certain that you only need to skip the first line then;

if(!$skipped)
{
    echo "Title row..skipping<br />";
    $skipped = true;
}
else
//do stuff
蓬勃野心 2024-09-14 20:07:16

我认为使用 foreach 会更优雅:

foreach data as item {
  if (item == "title") {
   echo "Skipping title<br/>";
  }
}

你现在的情况是,每次循环时都会检查 if (data[0] == "title")data[0] 将始终等于“title”,因此它的计算结果始终为 true。您可以增加 $index 变量并在底部附近执行类似 if (data[$index] == $title) then $index++ 的操作循环的一部分,但是当 foreach 本质上会为你做这件事时,为什么要这样做呢?

I think it'd be more elegant to use foreach:

foreach data as item {
  if (item == "title") {
   echo "Skipping title<br/>";
  }
}

How you have it now, you are checking if (data[0] == "title") every time you loop. data[0] will always equal "title", so it will always evaluate to true. You could increment an $index variable and do something like if (data[$index] == $title) then $index++ near the bottom of the loop, but why do that when foreach will essentially do that for you.

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