Finding elements of an array in another multi-dimensional array

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  • Sandman
    #1

    Finding elements of an array in another multi-dimensional array

    Hi,
    So I have 2 arrays:
    one contains userids. It may look like:
    user_id[0] =12,
    user_id[1] =30,
    user_id[2] =43

    The other is a multi-dimensional array with fields like:
    user_info [0] = Array
    (
    [user_id] =13
    [user_flag] =1
    [url] =http://www.example.com ?index,0
    )
    user_info[1] =Array
    {
    Array
    (
    [user_id] =120
    [user_flag] =1
    [address] =1234 Main St, Anytown, USA
    [url] =http://www.yahoo.com
    )
    user_info[2] =Array
    {
    Array
    (
    [user_id] =130
    [user_flag] =1
    [address] =134 Main St, Anytown, USA
    [url] =http://www.google.com
    )


    I need to find all elements in user_info, where user_info[]['user_id']
    == user_id[] for every element of user_id.

    Is there a quick and easy function to do this? My current loop looks
    like:
    for ($i=0; $i<count($user_ id); $i++) {
    for ($j=0; $j<=count($user _info); $j++) {
    if ($user_info[$j]["user_id"] == $user_id[$i]) {
    $newarray[$i] = $user_info[$j];
    break;
    }
    }
    }

    This is crappy though and I'd love to speed it up. Suggestions
    welcome.

    Thanks!
    EL

    Tags: None
    • Erwin Moller
      #2
      Re: Finding elements of an array in another multi-dimensional array

      Sandman wrote:
      Hi,
      So I have 2 arrays:
      one contains userids. It may look like:
      user_id[0] =12,
      user_id[1] =30,
      user_id[2] =43
      >
      The other is a multi-dimensional array with fields like:
      user_info [0] = Array
      (
      [user_id] =13
      [user_flag] =1
      [url] =http://www.example.com ?index,0
      )
      user_info[1] =Array
      {
      Array
      (
      [user_id] =120
      [user_flag] =1
      [address] =1234 Main St, Anytown, USA
      [url] =http://www.yahoo.com
      )
      user_info[2] =Array
      {
      Array
      (
      [user_id] =130
      [user_flag] =1
      [address] =134 Main St, Anytown, USA
      [url] =http://www.google.com
      )
      >
      >
      I need to find all elements in user_info, where user_info[]['user_id']
      == user_id[] for every element of user_id.
      >
      Is there a quick and easy function to do this? My current loop looks
      like:
      for ($i=0; $i<count($user_ id); $i++) {
      for ($j=0; $j<=count($user _info); $j++) {
      if ($user_info[$j]["user_id"] == $user_id[$i]) {
      $newarray[$i] = $user_info[$j];
      break;
      }
      }
      }
      >
      This is crappy though and I'd love to speed it up. Suggestions
      welcome.
      >
      Thanks!
      EL
      Hi Sandman,

      In my humble opinion that code is not crappy at all.
      Maybe you can find (a combination of) array functions, or even regexp if you
      feel really adventurous, that do the same job, but your approach is clear
      and easy to understand for anybody that reads the code later (including
      you).
      This is just my opinion, but if I should make a list for code, this is the
      order of importance:
      1) clearity of code
      2) speed of the code
      3) length of the code

      And I only care for the speed of the code if there is a reason to worry,
      like repetive SQL-queries.

      Regards,
      Erwin Moller

        Comment

        • Tom
          #3
          Re: Finding elements of an array in another multi-dimensional array

          On Feb 1, 6:28 am, Erwin Moller
          <since_humans_r ead_this_I_am_s pammed_too_m... @spamyourself.c omwrote:
          Sandman wrote:
          Hi,
          So I have 2 arrays:
          one contains userids. It may look like:
          user_id[0] =12,
          user_id[1] =30,
          user_id[2] =43
          >
          The other is a multi-dimensional array with fields like:
          user_info [0] = Array
          (
          [user_id] =13
          [user_flag] =1
          [url] =>http://www.example.com ?index,0
          )
          user_info[1] =Array
          {
          Array
          (
          [user_id] =120
          [user_flag] =1
          [address] =1234 Main St, Anytown, USA
          [url] =>http://www.yahoo.com
          )
          user_info[2] =Array
          {
          Array
          (
          [user_id] =130
          [user_flag] =1
          [address] =134 Main St, Anytown, USA
          [url] =>http://www.google.com
          )
          >
          I need to find all elements in user_info, where user_info[]['user_id']
          == user_id[] for every element of user_id.
          >
          Is there a quick and easy function to do this? My current loop looks
          like:
          for ($i=0; $i<count($user_ id); $i++) {
          for ($j=0; $j<=count($user _info); $j++) {
          if ($user_info[$j]["user_id"] == $user_id[$i]) {
          $newarray[$i] = $user_info[$j];
          break;
          }
          }
          }
          >
          This is crappy though and I'd love to speed it up. Suggestions
          welcome.
          >
          Thanks!
          EL
          >
          Hi Sandman,
          >
          In my humble opinion that code is not crappy at all.
          Maybe you can find (a combination of) array functions, or even regexp if you
          feel really adventurous, that do the same job, but your approach is clear
          and easy to understand for anybody that reads the code later (including
          you).
          This is just my opinion, but if I should make a list for code, this is the
          order of importance:
          1) clearity of code
          2) speed of the code
          3) length of the code
          >
          And I only care for the speed of the code if there is a reason to worry,
          like repetive SQL-queries.
          >
          Regards,
          Erwin Moller
          This might be cleaner, also less confusing since you don't have to do
          count( )'s:
          <?php
          foreach ( $user_id AS $id ) {
          foreach ( $user_info AS $array ) {
          if ( $array['user_id'] == $id ) {
          // your code here
          }
          }
          }
          ?>

            Comment

            • Sandman
              #4
              Re: Finding elements of an array in another multi-dimensional array

              Thanks Erwin. For some reason that script (which does more than just
              the loop) was taking a very long to load. After posting here, I stuck
              microtime() before and after the loop, but found that even when
              user_info[] had 10000 entries it took less than 10 ms. So the slowness
              is elsewhere.

              So I'm going to leave my loop like this, but look elsewhere for the
              slowness. Back to the drawing board

              Thanks everyone.
              S


              On Feb 1, 3:28 am, Erwin Moller
              <since_humans_r ead_this_I_am_s pammed_too_m... @spamyourself.c omwrote:
              Sandman wrote:
              Hi,
              So I have 2 arrays:
              one contains userids. It may look like:
              user_id[0] =12,
              user_id[1] =30,
              user_id[2] =43
              >
              The other is a multi-dimensional array with fields like:
              user_info [0] = Array
              (
              [user_id] =13
              [user_flag] =1
              [url] =>http://www.example.com ?index,0
              )
              user_info[1] =Array
              {
              Array
              (
              [user_id] =120
              [user_flag] =1
              [address] =1234 Main St, Anytown, USA
              [url] =>http://www.yahoo.com
              )
              user_info[2] =Array
              {
              Array
              (
              [user_id] =130
              [user_flag] =1
              [address] =134 Main St, Anytown, USA
              [url] =>http://www.google.com
              )
              >
              I need to find all elements in user_info, where user_info[]['user_id']
              == user_id[] for every element of user_id.
              >
              Is there a quick and easy function to do this? My current loop looks
              like:
              for ($i=0; $i<count($user_ id); $i++) {
              for ($j=0; $j<=count($user _info); $j++) {
              if ($user_info[$j]["user_id"] == $user_id[$i]) {
              $newarray[$i] = $user_info[$j];
              break;
              }
              }
              }
              >
              This is crappy though and I'd love to speed it up. Suggestions
              welcome.
              >
              Thanks!
              EL
              >
              Hi Sandman,
              >
              In my humble opinion that code is not crappy at all.
              Maybe you can find (a combination of) array functions, or even regexp if you
              feel really adventurous, that do the same job, but your approach is clear
              and easy to understand for anybody that reads the code later (including
              you).
              This is just my opinion, but if I should make a list for code, this is the
              order of importance:
              1) clearity of code
              2) speed of the code
              3) length of the code
              >
              And I only care for the speed of the code if there is a reason to worry,
              like repetive SQL-queries.
              >
              Regards,
              Erwin Moller

                Comment

                • Curtis
                  #5
                  Re: Finding elements of an array in another multi-dimensional array

                  On Thu, 01 Feb 2007 10:18:17 -0800, Sandman <enjoylife_9513 5@hotmail.com
                  wrote:
                  On Feb 1, 3:28 am, Erwin Moller
                  <since_humans_r ead_this_I_am_s pammed_too_m... @spamyourself.c omwrote:
                  >Sandman wrote:
                  Hi,
                  So I have 2 arrays:
                  one contains userids. It may look like:
                  user_id[0] =12,
                  user_id[1] =30,
                  user_id[2] =43
                  >>
                  The other is a multi-dimensional array with fields like:
                  user_info [0] = Array
                  (
                  [user_id] =13
                  [user_flag] =1
                  [url] =>http://www.example.com ?index,0
                  )
                  user_info[1] =Array
                  {
                  Array
                  (
                  [user_id] =120
                  [user_flag] =1
                  [address] =1234 Main St, Anytown, USA
                  [url] =>http://www.yahoo.com
                  )
                  user_info[2] =Array
                  {
                  Array
                  (
                  [user_id] =130
                  [user_flag] =1
                  [address] =134 Main St, Anytown, USA
                  [url] =>http://www.google.com
                  )
                  >>
                  I need to find all elements in user_info, where user_info[]['user_id']
                  == user_id[] for every element of user_id.
                  >>
                  Is there a quick and easy function to do this? My current loop looks
                  like:
                  for ($i=0; $i<count($user_ id); $i++) {
                  for ($j=0; $j<=count($user _info); $j++) {
                  if ($user_info[$j]["user_id"] == $user_id[$i]) {
                  $newarray[$i] = $user_info[$j];
                  break;
                  }
                  }
                  }
                  >>
                  This is crappy though and I'd love to speed it up. Suggestions
                  welcome.
                  >>
                  Thanks!
                  EL
                  >>
                  >Hi Sandman,
                  >>
                  >In my humble opinion that code is not crappy at all.
                  >Maybe you can find (a combination of) array functions, or even regexp
                  >if you
                  >feel really adventurous, that do the same job, but your approach is
                  >clear
                  >and easy to understand for anybody that reads the code later (including
                  >you).
                  >This is just my opinion, but if I should make a list for code, this is
                  >the
                  >order of importance:
                  >1) clearity of code
                  >2) speed of the code
                  >3) length of the code
                  >>
                  >And I only care for the speed of the code if there is a reason to worry,
                  >like repetive SQL-queries.
                  >>
                  >Regards,
                  >Erwin Moller
                  >
                  Thanks Erwin. For some reason that script (which does more than just
                  the loop) was taking a very long to load. After posting here, I stuck
                  microtime() before and after the loop, but found that even when
                  user_info[] had 10000 entries it took less than 10 ms. So the slowness
                  is elsewhere.
                  >
                  So I'm going to leave my loop like this, but look elsewhere for the
                  slowness. Back to the drawing board
                  >
                  Thanks everyone.
                  S
                  You could probably speed up the execution time by using better queries on
                  your database. It seems like a JOIN could take care of your PHP processing
                  there, but I may be/probably am wrong.

                  --
                  Curtis, http://dyersweb.com

                    Comment

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