Compare Array Values

[Anon]

Need a little insight....

I am using mysql_fetch_array to print some values from a mysql db.

However, depending the "next" row value I will print some things differently.

For example:

When I read a row in it has a date within it. If the "next row" to be read in has the same value as the current array date, I will print differently.

In short, is there a way to test an existing array value against a value that has not actually been read in yet....

Appreciate the valuable learning insight....

Thanks.

[mcliedtk]

Yes, it is possible to compare an existing value against the next value to be read, but you will need to actually read in this next value.

For example:

$saved_value = null;
while($result = mysql_fetch_array($array)) {
if($saved_value == $result) {
printA($result);
} else {
printB($result);
}
$saved_value = $result; //save latest value
}

You simply need to think of the problem as being shifted forward in time. In other words, think of the problem as: saved_value and newly_read_value; not as: next_value_in_line and newly_read_value.

I hope this helps.

-Michael

[Anon]

Thanks. Any ideas how to read in the 'next value' of the array to make the comparison BEFORE passing through the print loop once.

You see I need to check the date first, if indeed the date from the first record matches the second record, then I need to print a ROWSPAN of 4 to handle an additional record to be printed without having to print the date again.

This encompasses a look of:

---

Jan 2, 2001 | Run1 | blah | blah |

| Run2 | blah | blah |

So I need to plan as to whether or not I need to print a certain row span so I don't get:

---

Jan 2, 2001 | Run1 | blah | blah |

---

| Run2 | blah | blah |

Cystal clear...huh?!!

[mcliedtk]

Okay, I see what you are saying. Since you need to see one (or more) rows into the future, you need to compare the data of the top row to be printed with the data of all rows in the future that may need to be printed under the same date. I actually just ran into this problem a couple of days ago. My solution is basically what I described in my previous post, but since it wasn't what you were looking for, let me suggest an alternative.

This solution is a bit of a hack, but I feel it eliminates a lot of complexity. Basically, instead of messing with arrays, let HTML do the work. Simply, don't use rowspan as you had planned. Instead, insert the date into a row, then embed a table into the next row. Within this table print our all the data for the date. When you get to a new date, finish off the table, and repeat the process starting on a new row. This will involve - once again - inserting the current date into a row, and then inserting all the data for that date into a table that is contained in the following row.

This approach eliminates fancy logic to store and compare dates "into the future", and it neatens up the HTML a little. You will still need to do comparisons to determine when to add data to the table and when to start a new "date row/data row(table)". The comparisons can be done according to the description I posted previously. Remember to have your result set be sorted, so you can iterate through the arrays easily.

This sound better?

-Michael

[Anon]

Excellent post...It sounds good, I'll give it a shot and post my findings...

Thanks much!!

[Anon]

Take a look what I had been doing to generate my table...is this what you mean by handling within HTML? Do you have an example?

while ($row = mysql_fetch_array($result)){

$result2 = mysql_query("SELECT * FROM log3 limit $thisOffset, $recordLimit");
$p = 0;
while ($myrow = mysql_fetch_array($result2)){$value[$p] = $myrow[rundate];
$p++;
}

//row color
if ($counter%2 == 0){
$color = "#999999";
}
else $color = "#808080";

      if ($value[$lineIndex]==$value[$lineIndex + 1]){
      echo ("<tr>");
      //PREPARE TO HAVE 2 RUNS ON ONE DATE, PRINT DATE ONCE.
      echo "<TD BGCOLOR=$color ALIGN=CENTER VALIGN=TOP ROWSPAN=4><FONT FACE=verdana SIZE=2>";
      if ($row[rundate] == $prevdate)
      {
      }
      else
      {
      echo ($row[fdate]);
      }
      echo ("</TD>");
      echo "<TD BGCOLOR=$color ALIGN=CENTER VALIGN=TOP><FONT FACE=verdana SIZE=2>";
      echo ($row[workout_type]);
      echo ("<BR>");
      echo ($row[starttime]);
      echo ("</td>");
      echo "<TD BGCOLOR=$color ALIGN=CENTER VALIGN=TOP><FONT FACE=verdana SIZE=2>";
      echo ($row[distance]);
      echo (" miles");
      echo ("<br>");
      echo ("(");
      echo ($row[course]);
      echo (")");
      echo ("<br>");
      echo ("<br>");
      echo ($row[runtime]);
      echo ("<br>");
      echo ("(");
      echo ($row[runpace]);
      echo (" min/mile)");
      echo ("</td>");
      echo "<TD BGCOLOR=$color ALIGN=CENTER VALIGN=TOP><FONT FACE=verdana SIZE=2>";
      echo ("Shoes: ");
      echo ($row[shoes]);
      echo ("<br>");
      echo ("Weight: ");
      echo ("</td>");
      echo ("<tr>");
      echo "<TD COLSPAN=3 ALIGN=CENTER VALIGN=TOP BGCOLOR=$color><FONT FACE=verdana SIZE=2>";
      echo ($row[comments]);
      echo ("</td>");
      echo ("<tr>");
      }
      else
      {

      echo ("<tr>");
      echo "<TD BGCOLOR=$color ALIGN=CENTER VALIGN=TOP ROWSPAN=2><FONT FACE=verdana SIZE=2>";
      echo ($row[fdate]);
      echo ("</TD>");
      echo ("<BR>");
      echo "<TD BGCOLOR=$color ALIGN=CENTER VALIGN=TOP><FONT FACE=verdana SIZE=2>";
      echo ($row[workout_type]);
      echo ("<BR>");
      echo ($row[starttime]);
      echo ("</td>");
      echo "<TD BGCOLOR=$color ALIGN=CENTER VALIGN=TOP><FONT FACE=verdana SIZE=2>";
      echo ($row[distance]);
      echo (" miles");
      echo ("<br>");
      echo ("(");
      echo ($row[course]);
      echo (")");
      echo ("<br>");
      echo ("<br>");
      echo ($row[runtime]);
      echo ("<br>");
      echo ("(");
      echo ($row[runpace]);
      echo (" min/mile)");
      echo ("</td>");
      echo "<TD BGCOLOR=$color ALIGN=CENTER VALIGN=TOP><FONT FACE=verdana SIZE=2>";
      echo ("Shoes: ");
      echo ($row[shoes]);
      echo ("<br>");
      echo ("Weight: ");
      echo ("</td>");
      echo ("</tr>");
      //NEW ROW FOR COMMENTS
      echo ("<tr>");
      echo "<TD COLSPAN=3 ALIGN=CENTER VALIGN=TOP BGCOLOR=$color><FONT FACE=verdana SIZE=2>";
      echo ($row[comments]);
      echo ("</td>");
      echo ("</tr>");
      echo ("</tr>");
      }

$lineIndex++;
$counter++;
$prevdate = $row[rundate];

Thanks much!!!