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copied!<p>There is a big difference between "can evaluate if a certain variable is a number or not" and "evaluate if a certain variable is a positive number". Using the comparison signs require you to test it twice (Both <code>></code> & <code><=</code> or <code>>=</code> & <code><</code>) and may not be immediately obvious. <code>is_numeric</code> means you only need a single test and makes it quite obvious what you are doing.</p> <p>Also, a string will evaluate as 0, meaning it throws your idea out. Stick with the proper commands :)</p> <p><strong>As per comment:</strong> Well, in this case, you are asking for comparing <code>is_numeric</code> against a test for positive numbers, excluding 0. This is not the intent for <code>is_numeric</code>, so naturally it may not be necessary. If you do a mathematical check that involves 0 as the answer or as part of the range, you will need <code>is_numeric</code>, otherwise you won't need it. The first part of your question asks a different question, so:</p> <p><em>It seems that simple comparison signs >,>= and their reverse components can evaluate if a certain variable is a number or not</em> - <strong>Incorrect</strong></p> <p><em>Are there cases where <code>is_numeric()</code> usage is necessary for positive values (number >0)?</em> - <strong>No</strong></p> <p><em>It seems that using comparison signs above would determine if the variable is numeric</em> - <strong>No. They can determine if a variable is either <em>a non-zero number</em> or <em>unknown</em>, not numeric.</strong></p>

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