Question

// 40 characters string combine by 5 different fields
$field1 = apple;
$field2 = orange;
$field3 = pineapple;
$field4 = banana;
$field5 = strawberry;

// fields will be separated with a comma
$string = implode(", ", array_filter(array($field1, $field2, $field3, $field4, $field5)));

// string will be cut off at about 15th characters then make a break line           
$stringList = explode("\n", wordwrap($string , 15));

// 1st rowField takes the 1st line of string
$rowField1 = array_shift($nutritionalList);
$string = implode(" ",$stringList );
$stringList = explode("\n", wordwrap($string , 25));
$rowField2 = "From 1st Row continued" . "\n" . implode("\n", $stringList) . "\n \n";}

此输出将显示：

$rowField1 = "apple, orange"
$rowField2 = "From 1st Row continued \n pineapple, banana, strawberry"

但是，我的问题是如果$field3，$field4和$field5为NULL，我不想显示$rowField2，包括文字“From 1st Row续“

我尝试了IF / ELSE和ISSET程序：

if (isset($stringList)) {
   $rowField2 = "From 1st Row continued\n" . implode("\n", $stringList) . "\n\n";
}
else {
   $rowField2 = NULL;
}

但是$rowField2仍然显示“从第一行继续”。如果最后3个字段为NULL，我希望它不显示。

Answer 1

试试这个，它会输出“apple，orange”。

没事吗？

<?php
$field1 = 'apple';

$field2 = 'orange';

$field3 = '';

$field4 = '';

$field5 = '';

// fields will be seperated with a comma

$string = implode(", ", array_filter(array($field1, $field2, $field3, $field4, $field5)));

// string will be cut off at about 15th characters then make a break line

$stringList = explode("\n", wordwrap($string , 15));

// 1st rowField takes the 1st line of string

$rowField1 = array_shift($stringList);

$string = implode(" ",$stringList );

$stringList = explode("\n", wordwrap($string , 25));

$rowField2 = ( isset( $stringList[0] ) && !empty($stringList[0]) ) ? "From 1st Row continued" . "\n" . implode("\n", $stringList) . "\n \n" : '';
echo $rowField1;
echo "<br />";
echo $rowField2;
exit;
?>

Answer 2

我会使用条件：

if( isset($stringList) && count($stringList) > 0 ){
    // blah blah
}

Answer 3

$stringList将始终设置，但它并不总是包含内容。

不要使用empty，因为通过阅读它不清楚它是做什么的 - 一方面，empty("0")是TRUE！ - 即使在这种情况下，在数组上，它也可以工作。

我推荐的方法：

if (count($stringList)) {
   $rowField2 = "From 1st Row continued\n" . implode("\n", $stringList) . "\n\n";
}
else {
   $rowField2 = NULL;
}

PHP if语句不起作用？

3 个答案: