How do I include a yet to be defined variable inside a string? PHP

问题

For sake of performing less database queries and for clarity of code, I'd like include a yet to be defined variable inside a string. Later in the page, the variable will be declared and the string printed and evaluated. How do i do this?

$str="This $variable is delicious";

$array=array("Apple","Pineapple","Strawberry");

foreach($array as $variable)
{
  print "$str";
}

回答1:

You can use printf() (or sprintf() if you don't want to echo it):

$str = 'This %s is delicious';

foreach ($array as $variable) {
    printf($str, $variable);
}

回答2:

Use str_replace.

For example:

$str = "This is [VARIABLE] is delicious";
$array = array("Apple", "Pineapple", "Strawberry");

foreach($array as $variable)
{
    print str_replace('[VARIABLE]', $variable, $str);
}

回答3:

Why don't you just do:

$array=array("Apple","Pineapple","Strawberry");

foreach($array as $variable) {
    print "This $variable is delicious";
}

回答4:

I think you need php's sprintf function

http://php.net/manual/en/function.sprintf.php

or it can also be done using str_replace

http://in.php.net/manual/en/function.str-replace.php

回答5:

You are probably doing wrong way.
Learn to use templates and you will never need such odd things.
Just divide your code into 2 parts:

getting all required information
displaying a regular page or an error page

you will find that all your code become extremely neat and reusable

回答6:

$str='This $variable is delicious'; // so no variable interpolation is performed

$array=array("Apple","Pineapple","Strawberry");

foreach($array as $variable)
{
  // Warning! This is a very bad idea!
  // Using eval or system might create vulnerabilities!
  eval('$str="' . $str . '";');
  print $str;
}

来源：https://stackoverflow.com/questions/3624092/how-do-i-include-a-yet-to-be-defined-variable-inside-a-string-php

标签

php

variables