PHP字符串截取后入数组及从stdClass提取规则到指定数组索引

Got it, let's break down these two PHP tasks step by step!

This is a common task, and PHP's substr() function makes it straightforward. Here's a practical example that shows how to slice a string and add the result to an existing array:

// Example original string
$originalString = "HelloStackOverflow";
// Grab the first 5 characters (start at index 0, take 5 characters)
$slicedString = substr($originalString, 0, 5);
// Target array we want to add to
$targetArray = ["existing_item_1", "existing_item_2"];

// Add the sliced string to the array (two ways to do this)
$targetArray[] = $slicedString; // Quickest method
// OR: array_push($targetArray, $slicedString);

// Check the result
print_r($targetArray);

Notes: #

• substr($string, $start, $length) works by:
  • $start: The index to start slicing from (0 = beginning, negative numbers count from the end of the string)
  • $length: Optional number of characters to take (omit it to grab everything from $start to the end)
• Adjust the $start and $length values to match exactly which part of the string you need.

For this task, we need to group the rules_field_N, rules_condition_N, and rules_value_N properties from your stdClass object into nested arrays under $newdata['rules']. The trick is to spot the numeric suffix in each property name and group related fields by that number.

Here's a working implementation:

// Your sample stdClass object
$data = new stdClass();
$data->class = 'srt-fields';
$data->rules_field_1 = 1;
$data->rules_condition_1 = 0;
$data->rules_value_1 = 'text';
$data->rules_field_2 = 3;
$data->rules_condition_2 = 1;
$data->rules_value_2 = 'another_text';

// Initialize the new array
$newdata = [];
$newdata['rules'] = [];

// Loop through all properties in the stdClass object
foreach ($data as $key => $value) {
    // Skip the 'class' property since we don't need it for rules
    if ($key === 'class') continue;

    // Split the property name into parts (e.g., 'rules_field_1' becomes ['rules', 'field', '1'])
    $keyParts = explode('_', $key);
    $ruleIndex = end($keyParts); // Grab the numeric suffix (1, 2, etc.)
    $fieldType = $keyParts[1]; // Grab the field type (field, condition, value)

    // Initialize the rule array if it doesn't exist yet
    if (!isset($newdata['rules'][$ruleIndex])) {
        $newdata['rules'][$ruleIndex] = [];
    }

    // Assign the value to the correct field in the rule array
    $newdata['rules'][$ruleIndex][$fieldType] = $value;
}

// Re-index the rules array to get continuous numeric keys (0, 1, 2...) instead of 1, 2
$newdata['rules'] = array_values($newdata['rules']);

// Check the final structure
print_r($newdata['rules']);

What this does: #

1. Skips the class property since it's not part of the rules
2. Splits each rule-related property name to extract the numeric index and field type
3. Groups all fields with the same numeric index into a single array
4. Uses array_values() to reset the array keys so they're sequential (optional, but matches your desired output structure)

内容的提问来源于stack exchange，提问作者Sanjeev Aryal