如何评估数组中的每个值都是真的并在这种情况下在Php中做一些事情？

Question

I need to insert more than one row in a table

foreach($answers as $answer){
  $sql =<<<EOD
  INSERT INTO answer(`answer`, `question_id`) 
  VALUES ('$answer', (SELECT `id` FROM question WHERE `title` = '$title'))
  EOD;

  result_array[] = $this->db->query($sql);  
}   

I need to check each insert query is return True. What's control structure in Php can let me do something like:

if(each_value in result_array == 'True'){
  return 'success';
}

Answer 1

To make sure that you only have booleans in your array double negate the values returned by your query function (unless it already returns true/false, of course).:

result_array[] = !! $this->db->query($sql);

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Alternative #1

You could find the unique values between array(true) and your resulting array (result_array) and then see if the size is equal to zero using array_diff:

if (sizeof (array_diff (result_array, array (true)) == 0) {
  // all went well
}

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Alternative #2

If your resulting array only consists of values of either true or false you could hack your way through it using array_product such as in the below:

var_dump (array_product (array (true, false, true)));
var_dump (array_product (array (true, true, true)));

Output

int(0)
int(1)

array_product will multiply all the values of the array with each other, and since true evalutes to the integer 1 and false to the integer 0 we can use this to our advantage.

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Alternative #3 (don't modify source array)

You could use array_reduce with a callback to reduce your array to a single value, such as:

if (array_reduce (result_array, function ($a,$b) {return $a && $b;}, true) == true) {
  // all went well
}

This will implicitly cast every value of your array to a boolean, and give you the result you are after.

^{inline lambdas require more recent versions of PHP, a regular function name can be used as a callback if lambdas are unavailable}