Difference between revisions of "FormattingDecimals"
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<b>Setup:</b> |
<b>Setup:</b> |
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− | Use perl's <code>sprintf( format, number );</code> command to format the decimal. The <code>"%0.3f"</code> portion truncates after 3 decimal places and uses zeros (not spaces) to right-justify. For answers involving money, you should set <code>"%0.2f"</code> for two decimal places and zero filling (for example, <code>sprintf("%0.2f",0.5);</code> returns <code>0.50</code>). You can do a web search for more options to perl's <code>sprintf</code>, and also for WeBWorK's <code>contextCurrency.pl</code>. If you do further calculations with <code>$ |
+ | Use perl's <code>sprintf( format, number );</code> command to format the decimal. The <code>"%0.3f"</code> portion truncates after 3 decimal places and uses zeros (not spaces) to right-justify. For answers involving money, you should set <code>"%0.2f"</code> for two decimal places and zero filling (for example, <code>sprintf("%0.2f",0.5);</code> returns <code>0.50</code>). You can do a web search for more options to perl's <code>sprintf</code>, and also for WeBWorK's <code>contextCurrency.pl</code>. If you do further calculations with <code>$b</code>, be aware that numerical error may be an issue since you've reduced the number of decimal places. |
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Revision as of 14:16, 16 January 2010
Formatting Decimals: PG Code Snippet
We show how to format decimals for display in PG problems. Note that these are insertions, not a complete PG file. This code will have to be incorporated into the problem file on which you are working.
PG problem file | Explanation |
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loadMacros("PGstandard.pl","MathObjects.pl"); |
Initialization: Standard. |
$a = random(3,7,1); # log is natural log, and ln is also natural log $b = sprintf("%0.3f", log($a)/log(10) ); |
Setup:
Use perl's We used the logarithm change of base formula log_{10}(a) = log(a) / log(10) = ln(a) / ln(10) to get a logarithm base 10.
Note: If we load |
BEGIN_TEXT \( $b = \) \{ ans_rule(20) \} END_TEXT |
Main Text: Display the formatted number. |
ANS( $b->cmp() ); |
Answer Evaluation: Standard. |