I'm converting some fairly complex calculations from an Excel spreadsheet to PHP. I'm stuck on the conversion of Excel's FV function, which is defined like this:
FV( interest_rate, number_payments, payment, PV, Type )
I've been working on this for 2 hours and I'm definitely missing something. Essentially, I need to copy this functionality into an equivalent PHP function, taking all the parameters mentioned above.
Any help wouldbe veryappreciated.
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
Slightly modify the PHPExcel function library:
/** * FV * * Returns the Future Value of a cash flow with constant payments and interest rate (annuities). * * @param float $rate Interest rate per period * @param int $nper Number of periods * @param float $pmt Periodic payment (annuity) * @param float $pv Present Value * @param int $type Payment type: 0 = at the end of each period, 1 = at the beginning of each period * @return float */ function FV($rate = 0, $nper = 0, $pmt = 0, $pv = 0, $type = 0) { // Validate parameters if ($type != 0 && $type != 1) { return False; } // Calculate if ($rate != 0.0) { return -$pv * pow(1 + $rate, $nper) - $pmt * (1 + $rate * $type) * (pow(1 + $rate, $nper) - 1) / $rate; } else { return -$pv - $pmt * $nper; } } // function FV() echo FV(0.0149562574418, 4, 43.875, -250);Return 85.818510876629
// unit test
class ExcelTest extends \PHPUnit_Framework_TestCase { public function test_it_calculates_fv_value() { $test_data = [ [ 0.005, 10, -200, -500, 1, 2581.4033740601 ], [ 0.01, 12, -1000, null, null, 12682.503013197 ], [ 0.009166666667, 35, -2000, null, 1, 82846.246372418 ], [ 0.005, 12, -100, -1000, 1, 2301.4018303409 ], [ 0.004166666667, 60, -1000, null, null, 68006.082841536 ], [ 0.025, 16, -2000, 0, 1, 39729.460894166 ], [ 0.0, 12, -100, -100, null, 1300 ] ]; $test_case_id = 0; foreach($test_data as $test_case) { $test_case_id++; list($rate, $nper, $pmt, $pv, $type, $expected_result) = $test_case; $this->assertEquals($expected_result, Excel::FV($rate, $nper, $pmt, $pv, $type), "Test case $test_case_id failed", 0.0000001); } } }