PHP log10函数代码示例

 /**
  * 
  * @return type json dell' array dei prodotti della home
  */
 public function ProdottiInEvidenza()
 {
     $ProdottoDAO = new FProdotto();
     $risultato = $ProdottoDAO->ContaProdotti();
     $risultato = $risultato[0]["COUNT(Id)"];
     //Risultato contiene il num di prodotti presenti nel Catalogo
     $Indicicasuali = array();
     for ($index = 0; $index < 6; $index++) {
         $Indicicasuali[] = rand(1, $risultato);
     }
     $Indicicasuali = array_unique($Indicicasuali);
     while (count($Indicicasuali) < 6) {
         $Indicicasuali[] = rand(1, $risultato);
         $Indicicasuali = array_unique($Indicicasuali);
     }
     $CRicercaProdotto = new CRicercaProdotto();
     $ArrayProdotti = array();
     foreach ($Indicicasuali as $key => $value) {
         for ($i = 0; $i < 2 - log10($value); $i++) {
             $value = "0" . $value;
         }
         $value = "P" . $value;
         $ArrayProdotti[] = $CRicercaProdotto->RicercaPerId($value);
     }
     $JsonRisultato = json_encode($ArrayProdotti);
     return $JsonRisultato;
 }

 /**
  * Decode a geohash and return an array with decimal lat,long in it
  */
 public function decode($hash)
 {
     //decode hash into binary string
     $binary = "";
     $hl = strlen($hash);
     for ($i = 0; $i < $hl; $i++) {
         $binary .= $this->codingMap[substr($hash, $i, 1)];
     }
     //split the binary into lat and log binary strings
     $bl = strlen($binary);
     $blat = "";
     $blong = "";
     for ($i = 0; $i < $bl; $i++) {
         if ($i % 2) {
             $blat = $blat . substr($binary, $i, 1);
         } else {
             $blong = $blong . substr($binary, $i, 1);
         }
     }
     //now concert to decimal
     $lat = $this->binDecode($blat, -90, 90);
     $long = $this->binDecode($blong, -180, 180);
     //figure out how precise the bit count makes this calculation
     $latErr = $this->calcError(strlen($blat), -90, 90);
     $longErr = $this->calcError(strlen($blong), -180, 180);
     //how many decimal places should we use? There's a little art to
     //this to ensure I get the same roundings as geohash.org
     $latPlaces = max(1, -round(log10($latErr))) - 1;
     $longPlaces = max(1, -round(log10($longErr))) - 1;
     //round it
     $lat = round($lat, $latPlaces);
     $long = round($long, $longPlaces);
     return array($lat, $long);
 }

 /**
  * @dataProvider twoAxisDataProvider
  **/
 public function testTwoAxis($firstAxisData, $secondtAxisData, $result)
 {
     foreach ($result as $chartClass => $expectedString) {
         $views = GoogleChartDataSet::create()->setData($firstAxisData);
         $clicks = GoogleChartDataSet::create()->setData($secondtAxisData);
         $chart = new $chartClass();
         if ($chart->getData()->isNormalized()) {
             if ($views->getMax() >= 10) {
                 $base = pow(10, floor(log10($views->getMax())));
             } else {
                 $base = 0.1;
             }
             $views->setBase($base);
             if ($clicks->getMax() >= 10) {
                 $base = pow(10, floor(log10($clicks->getMax())));
             } else {
                 $base = 0.1;
             }
             $clicks->setBase($base);
         }
         $viewAxis = GoogleChartAxis::create(new GoogleChartAxisType(GoogleChartAxisType::Y))->setRange($views->getMinMax());
         $clickAxis = GoogleChartAxis::create(new GoogleChartAxisType(GoogleChartAxisType::R))->setRange($clicks->getMinMax());
         if ($chart->getData()->isNormalized()) {
             $viewAxis->setInterval($views->getBase());
             $clickAxis->setInterval($clicks->getBase());
         }
         $chart->setSize(GoogleChartSize::create()->setWidth(300)->setHeight(300))->addAxis($viewAxis)->addLine(GoogleChartLine::create()->setTitle('Показы')->setColor(Color::create('336699'))->setValue($views))->addAxis($clickAxis)->addLine(GoogleChartLine::create()->setTitle('Клики')->setColor(Color::create('339911'))->setValue($clicks));
         $this->assertEquals($expectedString, $chart->toString());
     }
 }

/**
 * Determine if the integer is palindromic.  This works by comparing the most significant and least significant digits
 * at each iteration for equality.  If they are equal it keeps iterating.  If it makes it half-way through the integer
 * with no differences, the integer is palindromic.
 * The most significant digit is found by dividing the integer by 10^the number of digits in the integer.  If the
 * integer is 98789 then the number of digits is 5, then 98789 is divided by 10^4(10000).  This results in
 * 98789 / 10000 = 9.8789.  This value is treated as an integer so it's just 9.
 * The least significant digit is found by calculating the modulo of the integer and 10.  If the integer is 98789 then
 * this results in 98789 % 10 = 9.
 * If the digits match in an iteration then the modulo of the original iterator and 10^the number of digits in the
 * integer is found.  This becomes the new integer value.  If the integer is 98789 then this results in 98789 % 10000 =
 * 8789.  Then the copy of the original integer is divided by 10 to remove the least significant digit.  If the copy of
 * the original integer is 98789 this results in 98789 / 10 = 9878.9.  This is treated as an integer so it's just 9878.
 * After this happens we have two new integers, 8789 and 9878 which are the result of the original integer 98789 with
 * the most significant and least significant digits stripped, respectively.
 *
 * If the number is 98789:
 * $numberOfDigits = 5
 * $msdShift = 10000
 *
 * Iteration 1:
 * 98789 / 10000 = 9.8789 rounded to 9 AND 98789 % 10 = 9 so we continue
 * $integer = 98789 % 10000 = 8789
 * $msdShift = 10000 / 10 = 1000
 * $integerRemaining = 98789 / 10 = 9878
 *
 * Iteration 2:
 * 8789 / 1000 = 8.789 rounded to 8 AND 9878 % 10 = 8 so we continue
 * $integer = 8789 % 1000 = 789
 * $msdShift = 1000 / 10 = 100
 * $integerRemaining = 9878 / 10 = 987
 *
 * Iteration 3:
 * 789 / 100 = 7.89 rounded to 7 AND 987 % 10 = 7 so we continue
 * $integer = 789 % 100 = 89
 * $msdShift = 100 / 10 = 10
 * $integerRemaining = 987 / 10 = 98
 *
 * Iteration 4:
 * 89 / 10 = 8.9 rounded to 8 AND 98 % 10 = 8 so we continue
 * $integer = 89 % 10 = 9
 * $msdShift = 10/10 = 1
 * $integerRemaining = 98 / 10 = 9
 *
 * We have reached the middle so we are done, 98789 is palindromic
 *
 *
 * If the number is 9587:
 * $numberOfDigits = 4
 * $msdShift = 1000
 *
 * Iteration 1:
 * 9587 / 1000 = 9.587 rounded to 9 AND 9587 % 10 = 7 so 9587 is not a palindrome
 *
 * @param $integer
 * @return bool
 */
function isPalindromic($integer)
{
    if (!is_numeric($integer)) {
        throw new \InvalidArgumentException('$integer must be a number');
    }
    $integer = (int) $integer;
    if ($integer < 0) {
        return false;
    }
    if ($integer === 0) {
        return true;
    }
    $numberOfDigits = floor(log10($integer)) + 1;
    $integerRemaining = $integer;
    $msdShift = pow(10, $numberOfDigits - 1);
    for ($i = 0; $i < $numberOfDigits / 2; $i++) {
        if ((int) ($integer / $msdShift) != (int) ($integerRemaining % 10)) {
            return false;
        }
        $integer %= $msdShift;
        $msdShift /= 10;
        $integerRemaining /= 10;
    }
    return true;
}

 public function actionView($id)
 {
     if ($id <= 0) {
         $this->goHome();
     }
     $allCategory = Category::find()->asArray()->all();
     $arrayCategoryIdName = ArrayHelper::map($allCategory, 'id', 'name');
     $arrSubCat = Category::getArraySubCatalogId($id, $allCategory);
     /****** 价格筛选 ****/
     $result = (new Query())->select('min(price) as min, max(price) as max')->from('product')->where(['category_id' => $arrSubCat, 'status' => Status::STATUS_ACTIVE])->one();
     $min = $result['min'];
     $max = $result['max'];
     if ($max > $min && $max > 0) {
         // 计算跨度
         $priceGrade = 0.0001;
         for ($i = -2; $i < log10($max); $i++) {
             $priceGrade *= 10;
         }
         $span = ceil(($max - $min) / 5 / $priceGrade) * $priceGrade;
         if ($span == 0) {
             $span = $priceGrade;
         }
         // 计算价格的起点和终点
         for ($i = 1; $min > $span * $i; $i++) {
         }
         for ($j = 1; $min > $span * ($i - 1) + $priceGrade * $j; $j++) {
         }
         $priceFilter['start'] = $span * ($i - 1) + $priceGrade * ($j - 1);
         for (; $max >= $span * $i; $i++) {
         }
         $priceFilter['end'] = $span * $i + $priceGrade * ($j - 1);
         $priceFilter['span'] = $span;
     }
     /****** 价格筛选 end ****/
     /****** 品牌筛选 start ****/
     $result = (new Query())->select('distinct(brand_id)')->from('product')->where(['category_id' => $arrSubCat, 'status' => Status::STATUS_ACTIVE])->all();
     $ids = ArrayHelper::map($result, 'brand_id', 'brand_id');
     $brandFilter = Brand::find()->where(['id' => $ids])->orderBy(['name' => SORT_ASC])->all();
     /****** 品牌筛选 end ****/
     $query = Product::find()->where(['category_id' => $arrSubCat, 'status' => Status::STATUS_ACTIVE]);
     // 如果选择了价格区间
     if (Yii::$app->request->get('max')) {
         $min = intval(Yii::$app->request->get('min'));
         $max = intval(Yii::$app->request->get('max'));
         if ($min >= 0 && $max) {
             $query->andWhere(['and', ['>', 'price', $min], ['<=', 'price', $max]]);
         }
     }
     // 如果选择了品牌
     if (Yii::$app->request->get('brand_id')) {
         $brandId = intval(Yii::$app->request->get('brand_id'));
         if ($brandId >= 0) {
             $query->andWhere(['brand_id' => $brandId]);
         }
     }
     // 侧边热销商品
     $sameCategoryProducts = Product::find()->where(['category_id' => $id])->orderBy(['sales' => SORT_DESC])->limit(5)->all();
     $dataProvider = new ActiveDataProvider(['query' => $query, 'pagination' => ['defaultPageSize' => Yii::$app->params['defaultPageSizeProduct']], 'sort' => ['defaultOrder' => ['created_at' => SORT_DESC]]]);
     return $this->render('view', ['model' => $this->findModel($id), 'allCategory' => $allCategory, 'arrayCategoryIdName' => $arrayCategoryIdName, 'products' => $dataProvider->getModels(), 'pagination' => $dataProvider->pagination, 'priceFilter' => isset($priceFilter) ? $priceFilter : null, 'brandFilter' => $brandFilter, 'sameCategoryProducts' => $sameCategoryProducts]);
 }

function pctcolour($pct)
{
    if ($pct == 100) {
        $fg = 'white';
        $bg = 'black';
    }
    if ($pct < 100) {
        $grn = (2.0 - log10($pct)) * 255;
        if ($grn < 0) {
            $grn = 0;
        }
        if ($grn > 255) {
            $grn = 255;
        }
        if ($grn > 190) {
            $fg = 'blue';
        } else {
            $fg = 'white';
        }
        $bg = sprintf("#00%02x00", $grn);
    }
    if ($pct > 100) {
        $red = (log10(pow($pct, 4.0)) - 8.0) / 3.0 * 255;
        if ($red < 0) {
            $red = 0;
        }
        if ($red > 255) {
            $red = 255;
        }
        $fg = 'white';
        $bg = sprintf("#%02x0000", $red);
    }
    return array($fg, $bg);
}

 function Generate($level)
 {
     if ($level <= 3) {
         $base = rand(2, 3);
         $result = rand(5, 10);
     } elseif ($level <= 6) {
         $base = rand(4, 5);
         $result = rand(10, 15);
     } else {
         $base = rand(6, 7);
         $result = rand(15, 20);
     }
     // // Original exercise
     // $base = 2;
     // $result = 10;
     $question = 'Oldja meg a következő egyenletet a valós számok halmazán! Válaszát három tizedesjegyre kerekítve adja meg!$$' . $base . '^x=' . $result . '$$';
     $exponent1 = log10($result) / log10($base);
     $exponent2 = round2($exponent1, 5);
     $correct = round2($exponent1, 3);
     $solution = '$' . $correct . '$';
     $page[] = 'Vegyük mindkét oldal $10$-es alapú logaritmusát:$$\\log_{10}\\left(' . $base . '^x\\right)=\\log_{10}' . $result . '$$';
     $page[] = '<div class="alert alert-info"><strong>Logaritmus azonossága:</strong><br />Hatvány logaritmusa egyenlő az alap logaritmusának és a kitevőnek a szorzatával:$$\\log_ab^k=k\\cdot\\log_ab$$</div>';
     $page[] = 'Az azonosság felhasználásával át tudjuk írni a baloldali kifejezést:$$x\\cdot\\log_{10}' . $base . '=\\log_{10}' . $result . '$$';
     $hints[] = $page;
     $page = [];
     $page[] = 'Osszuk el mindkét oldalt $\\log_{10}' . $base . '$-' . With($base) . '!$$x=\\frac{\\log_{10}' . $result . '}{\\log_{10}' . $base . '}\\approx' . $exponent2 . '$$';
     $page[] = '<b>Megjegyzés</b>: a számológépen a tízes alapú logaritmust a <b>log</b> gomb jelöli:<div class="text-center"><kbd>' . $result . '</kbd> <kbd>log</kbd> <kbd>&divide;</kbd> <kbd>' . $base . '</kbd>  <kbd>log</kbd> <kbd>=</kbd></div>';
     $page[] = 'A megoldás három tizedesjegyre kerekített értéke <span class="label label-success">$' . $correct . '$</span>.';
     $hints[] = $page;
     return array('question' => $question, 'correct' => $correct, 'solution' => $solution, 'hints' => $hints);
 }

function convfunc($valtoconv, $convtowhat)
{
    if ($valtoconv == 0) {
        return 0;
    }
    if (strlen($valtoconv) == 1) {
        return $valtoconv;
    }
    switch ($convtowhat) {
        case 1:
            $a = $valtoconv / 20.0;
            $b = pow(10, $a);
            $c = $b * sqrt(8);
            $x = $c;
            error_log("a = {$a}, b = {$b}, c = {$c}");
            return $x;
        case 2:
            $a = $valtoconv / sqrt(8);
            $b = log10($a);
            $c = 20.0 * $b;
            $x = $c;
            error_log("a = {$a}, b = {$b}, c = {$c}");
            return $x;
        default:
            return $valtoconv;
    }
}

 public function FromReal($aVal, $aPrecision = 2)
 {
     // Convert a floating point number to scientific notation
     $neg = 1.0;
     if ($aVal < 0) {
         $neg = -1.0;
         $aVal = -$aVal;
     }
     $l = floor(log10($aVal));
     $a = sprintf("%0." . $aPrecision . "f", round($aVal / pow(10, $l), $aPrecision));
     $a *= $neg;
     if ($this->iSimple && ($a == 1 || $a == -1)) {
         $a = '';
     }
     if ($a != '') {
         $this->t = $a . ' * 10';
     } else {
         if ($neg == 1) {
             $this->t = '10';
         } else {
             $this->t = '-10';
         }
     }
     $this->iSuper = $l;
 }

 public function decode($hash)
 {
     $binary = "";
     $hl = strlen($hash);
     for ($i = 0; $i < $hl; $i++) {
         $binary .= $this->codingMap[substr($hash, $i, 1)];
     }
     $bl = strlen($binary);
     $blat = "";
     $blong = "";
     for ($i = 0; $i < $bl; $i++) {
         if ($i % 2) {
             $blat = $blat . substr($binary, $i, 1);
         } else {
             $blong = $blong . substr($binary, $i, 1);
         }
     }
     $lat = $this->binDecode($blat, -90, 90);
     $long = $this->binDecode($blong, -180, 180);
     $latErr = $this->calcError(strlen($blat), -90, 90);
     $longErr = $this->calcError(strlen($blong), -180, 180);
     $latPlaces = max(1, -round(log10($latErr))) - 1;
     $longPlaces = max(1, -round(log10($longErr))) - 1;
     $lat = round($lat, $latPlaces);
     $long = round($long, $longPlaces);
     return array($lat, $long);
 }

 /**
  * From roman to decimal numeral system
  *
  * @param    string    $sRoman
  * @return    integer                   0 on failure.
  */
 public static function toDecimal($sRoman)
 {
     if (!is_string($sRoman)) {
         return 0;
     }
     $iStrLen = strlen($sRoman);
     $iDoubleSymbol = $iDec = $iPos = 0;
     foreach (self::$asRomanTransTable as $iNum => $sSymbol) {
         $iLen = strlen($sSymbol);
         $iCount = 0;
         if ($iDoubleSymbol) {
             --$iDoubleSymbol;
             continue;
         }
         # Mind the fact that 1000 in the Roman numeral system may be represented by M or i.
         while (($sChunk = substr($sRoman, $iPos, $iLen)) == $sSymbol || $iNum < 10000.0 && $sChunk == strtr($sSymbol, 'iM', 'Mi')) {
             if ($iLen == 2) {
                 $iDoubleSymbol = 3 - 2 * ($iNum % 3);
             }
             $iDec += $iNum;
             $iPos += $iLen;
             # All symbols that represent 1eX may appear at maximum three times. All other symbols may only represent one time in a roman number.
             if (fmod(log10($iNum), 1) || ++$iCount == 3) {
                 break;
             }
         }
         if ($iPos == $iStrLen) {
             break;
         }
     }
     # If there are symbols left, then the number was mallformed (following default rules (M = 1000 and i = 1000)).
     return $iPos == $iStrLen ? $iDec : 0;
 }

 /** {@inheritdoc} */
 protected function execute(InputInterface $input, OutputInterface $output)
 {
     $type = $input->getOption('type');
     if (!in_array($type, array('error', 'exception'))) {
         throw new \LogicException('Type must be either "error" or "exception"');
     }
     $count = intval($input->getOption('count'));
     $digits = floor(log10($count) + 1);
     /** @var ErrorHandler $errorHandler */
     $errorHandler = $this->getContainer()->get('error_handler');
     $metadata = new Metadata();
     $metadata->addCategories($input->getArgument('category'));
     $output->writeln('<fg=cyan>Creating errors</fg=cyan>');
     for ($i = 1; $i <= $count; ++$i) {
         switch ($type) {
             case 'error':
                 $error = new ErrorException('TEST ERROR', E_USER_ERROR, __FILE__, __LINE__);
                 $errorHandler->handleError($error, $metadata);
                 break;
             case 'exception':
                 $errorHandler->handleException(new \Exception(), $metadata);
                 break;
         }
         $output->writeln(sprintf("<comment>[%{$digits}d/%{$digits}d]</comment> <info>OK</info>", $i, $count));
     }
     $output->writeln('<info>DONE</info>');
 }

 /**
  * Set the power
  *
  * @param   int p power
  * @throws  lang.IllegalArgumentException in case the parameter p contains an illegal value
  */
 public function setPoweredBy($p)
 {
     if (!($x = log10($p / 6.1)) || floor($x) != $x) {
         throw new IllegalArgumentException($p . ' not allowed');
     }
     $this->poweredBy = $p;
 }

function good_125step($x)
{
    $n = (int) floor(log10($x));
    $residue = $x / pow(10, $n);
    # Equality test on floats isn't usually safe, but it works here.
    return $residue == 1 || $residue == 2 || $residue == 5;
}

function radixSortInt($array)
{
    $maxPow = floor(log10(max($array)));
    for ($i = 0; $i <= $maxPow; $i++) {
        // makes an array of buckets to sort mod into
        $bucketArray = [];
        for ($j = -9; $j < 10; $j++) {
            $bucketArray[$j] = 0;
        }
        foreach ($array as $element) {
            $bucketArray[$element / 10 ** $i % 10]++;
        }
        $bucketArray[-9]--;
        for ($j = -8; $j < 10; $j++) {
            $bucketArray[$j] += $bucketArray[$j - 1];
        }
        $arraySorted = $array;
        for ($j = count($array) - 1; $j >= 0; $j--) {
            $arraySorted[$bucketArray[$array[$j] / 10 ** $i % 10]] = $array[$j];
            $bucketArray[$array[$j] / 10 ** $i % 10]--;
        }
        $array = $arraySorted;
    }
    return $array;
}