数组根据值 如何进行合并处理

Question

问题 数组1如何 可以组合成数组2的形式？ 数组1 $a = [ [ 'tagId' => '43', 'streetName' => '锦春路', 'placecode' => '010170' ], [ 'tagId' => '44', 'streetName' => '滨湖路', 'placecode' => '010203' ], [ 'tagId' => '44', 'streetName' => '滨湖路', 'placecode' => '010204' ] ]; 打印出结果 array (size=3) 0 => array (size=3) 'tagId' => string '43' (length=2) 'streetName' => string '锦春路' (length=9) 'placecode' => string '010170' (length=6) 1 => array (size=3) 'tagId' => string '44' (length=2) 'streetName' => string '滨湖路' (length=9) 'placecode' => string '010203' (length=6) 2 => array (size=3) 'tagId' => string '44' (length=2) 'streetName' => string '滨湖路' (length=9) 'placecode' => string '010204' (length=6) 数组2 $b = [ [ 'tagId' => '43', 'streetName' => '锦春路', 'placeCodes' => ['010170'] ], [ 'tagId' => '44', 'streetName' => '滨湖路', 'placeCodes' => ['010203','010204'] ] ]; 打印出结果 array (size=2) 0 => array (size=3) 'tagId' => int 43 'streetName' => string '锦春路' (length=9) 'placeCodes' => array (size=1) 0 => string '010170' (length=6) 1 => array (size=3) 'tagId' => int 44 'streetName' => string '滨湖路' (length=9) 'placeCodes' => array (size=2) 0 => string '010203' (length=6) 1 => string '010204' (length=6)