a之间有什么区别。 a和一个{在变量的php回声中？ [重复]

Question

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• Difference between period and comma when concatenating with echo versus return? 6 answers

In PHP how do you know if you should use each form of echo, and what is the proper uses for each:

with the period:

 echo"<div>
        <img src='".$row['image']."'>
        ".$row['text']."
    </div>

with the comma:

echo"<div>
    <img src='",$row['image'],"'>
    ",$row['text'],"
</div>

with the {}:

echo"<div>
    <img src='{$row['image']}'>
    {$row['text']}
</div>

preset:

$image=$row['image'];
$text=$row['text'];
    echo"<div>
        <img src='$image'>
        $text
    </div>

More specifically I'm looking for the difference in how PHP will add the text to the HTML dump on the front end.

</div>

Answer 1

with period:

echo"<div>
        <img src='".$row['image']."'>
        ".$row['text']."
    </div>";

src='".$row['image']."' denotes the concatenation of $row['image']

with comma:

echo"<div>
    <img src='",$row['image'],"'>
    ",$row['text'],"
</div>";

^The comma , defines the string separation in the above example.

preset:

$image=$row['image'];
$text=$row['text'];
    echo"<div>
        <img src='$image'>
        $text
    </div>

^While this would still work with single '$image' A better practice would be '".$row['image']."' wrapped around quotes, i.e. below:

echo "<div>
    <img src='".$image."'>
    ".$text."
</div>";

Note: Keeping it simple, . for concatenation and , for separation.

^An Example:

<?php
$str = "Hawas" . "Ka" . "Pujaari";

echo $str;

$str2 = "Hawas, " . "Ka, " . "Pujaari";

echo  $str2;
?>