Eval()vs.substitute(): Difference between revisions
Jump to navigation
Jump to search
No edit summary |
(added historical tag and gave updated problem link) |
||
| (2 intermediate revisions by 2 users not shown) | |||
| Line 1: | Line 1: | ||
{{historical}} | |||
<p style="font-size: 120%;font-weight:bold">This problem has been replaced with [https://openwebwork.github.io/pg-docs/sample-problems/problem-techniques/EvalVersusSubstitute.html a newer version of this problem]</p> | |||
The aim of this page is to demonstrate the difference between <code>eval()</code> and <code>substitute</code>. | The aim of this page is to demonstrate the difference between <code>eval()</code> and <code>substitute</code>. | ||
| Line 10: | Line 14: | ||
$f = Compute(sqrt(3x + 1); | $f = Compute(sqrt(3x + 1); | ||
$fx = $f-> | $fx = $f->substitute(x=>"3"); | ||
displays (3.16228) | displays (3.16228) | ||
| Line 16: | Line 20: | ||
One of the biggest differences between <code>eval()</code> and <code>substitute</code> is when they are used in conjunction with flags such as <code>reduceConstants</code> and <code>reduceConstantFunctions</code>, which is described in more detail at:[[FormattingCorrectAnswers:_NumbersAndFormulas]] | One of the biggest differences between <code>eval()</code> and <code>substitute</code> is when they are used in conjunction with flags such as <code>reduceConstants</code> and <code>reduceConstantFunctions</code>, which is described in more detail at:[[FormattingCorrectAnswers:_NumbersAndFormulas]] | ||
[[Category:Authors]] | |||
Latest revision as of 13:32, 28 June 2023
This problem has been replaced with a newer version of this problem
The aim of this page is to demonstrate the difference between eval() and substitute.
Note:PGLabs is an efficient way to check code.
$f = Compute(sqrt(3x + 1); $fx = $f->eval(x=>"3"); displays 3.16228
The correct answer is a number.
$f = Compute(sqrt(3x + 1); $fx = $f->substitute(x=>"3"); displays (3.16228)
The correct answer is a formula (hence the parenthesis)
One of the biggest differences between eval() and substitute is when they are used in conjunction with flags such as reduceConstants and reduceConstantFunctions, which is described in more detail at:FormattingCorrectAnswers:_NumbersAndFormulas