PHP sonlar va matematik funksiyalar

Narx hisoblash, foiz, o’rtacha qiymat, tasodifiy tanlov — bularning barchasi sonlar bilan ishlashni talab qiladi.

Butun va kasr

PHP

<?php
$butun = 42;
$kasr = 19.99;

var_dump($butun);
var_dump($kasr);

var_dump(10 / 2);
var_dump(10 / 4);

10 / 2 natijasi int(5) emas, float(5) — PHP’da bo’lish deyarli har doim float qaytaradi.

Yaxlitlash

PHP

<?php
$son = 19.567;

echo round($son), "\n";
echo round($son, 1), "\n";
echo round($son, 2), "\n";

echo ceil($son), "\n";
echo floor($son), "\n";

echo round(-2.5), "\n";
echo intval($son);

round — matematik yaxlitlash (ikkinchi argument — xona soni);
ceil — yuqoriga, floor — pastga;
intval — kasr qismini shunchaki tashlab yuboradi.

Farqni ko’ring:

PHP

<?php
$sonlar = [2.3, 2.5, 2.7, -2.3, -2.7];

foreach ($sonlar as $n) {
  printf("%5.1f  round=%3d  ceil=%3d  floor=%3d\n",
      $n, round($n), ceil($n), floor($n));
}

Kasr aniqligi

PHP

<?php
$natija = 0.1 + 0.2;

echo $natija, "\n";
var_dump($natija === 0.3);
printf("%.20f\n", $natija);

var_dump(abs($natija - 0.3) < 0.00001);

Kasr sonlarni === bilan solishtirmang

Kompyuter kasr sonlarni ikkilik sanoqda saqlaydi va 0.1 aniq ifodalanmaydi. Bu PHP’ning kamchiligi emas — deyarli barcha tillarda shunday.

Pul bilan ishlashda kasr umuman ishlatilmaydi: summani tiyinda (butun son) saqlang yoki bcmath kengaytmasidan foydalaning:

$narx_tiyin = 1250050;   // 12 500.50 so'm

Matnni songa o’girish

Forma orqali kelgan ma’lumot har doim matn bo’ladi:

PHP

<?php
$matn = "42";

var_dump((int) $matn);
var_dump((float) "19.99");
var_dump(intval("100"));

var_dump((int) "42abc");
var_dump((int) "abc");
var_dump(is_numeric("42"));
var_dump(is_numeric("42abc"));

Avval tekshiring

(int) "abc" jimgina 0 beradi — bu xavfli. Foydalanuvchi ma’lumotini o’girishdan oldin is_numeric bilan tekshiring yoki filter_var ishlating:

$son = filter_var($kiritilgan, FILTER_VALIDATE_INT);
if ($son === false) {
    echo "Butun son kiriting";
}

PHP

<?php
$qiymatlar = ["42", "19.99", "abc", "", "0"];

foreach ($qiymatlar as $q) {
  $natija = filter_var($q, FILTER_VALIDATE_INT);
  printf("%-8s → %s\n", "'$q'", $natija === false ? "SON EMAS" : $natija);
}

Matematik funksiyalar

PHP

<?php
echo abs(-15), "\n";
echo pow(2, 10), "\n";
echo 2 ** 10, "\n";
echo sqrt(144), "\n";
echo max(3, 7, 2), "\n";
echo min([10, 4, 8]), "\n";
echo M_PI;

max va min alohida argumentlarni ham, massivni ham qabul qiladi.

Tasodifiy son

PHP

<?php
echo rand(1, 6), "\n";
echo random_int(1, 6), "\n";

$sonlar = [];
for ($i = 0; $i < 5; $i++) {
  $sonlar[] = random_int(1, 100);
}
print_r($sonlar);

$mevalar = ["olma", "banan", "uzum"];
echo $mevalar[array_rand($mevalar)];

Foiz hisoblash

PHP

<?php
function chegirma(float $narx, float $foiz): float {
  return $narx * (1 - $foiz / 100);
}

function qqsQoshib(float $narx, float $qqs = 12): float {
  return $narx * (1 + $qqs / 100);
}

$narx = 250000;

echo "Asl narx:    ", number_format($narx, 0, ',', ' '), "\n";
echo "15% chegirma: ", number_format(chegirma($narx, 15), 0, ',', ' '), "\n";
echo "QQS bilan:    ", number_format(qqsQoshib($narx), 0, ',', ' '), "\n";

$eski = 200000;
$yangi = 250000;
$oshish = (($yangi - $eski) / $eski) * 100;
echo "O'sish: ", round($oshish, 1), "%";

Bo’lish va qoldiq

PHP

<?php
echo 17 / 5, "\n";
echo intdiv(17, 5), "\n";
echo 17 % 5, "\n";

$jami_daqiqa = 197;
$soat = intdiv($jami_daqiqa, 60);
$daqiqa = $jami_daqiqa % 60;
echo "$soat soat $daqiqa daqiqa";

Nolga bo'lish

PHP 8 da nolga bo’lish xato beradi (avval ogohlantirish edi):

echo 10 / 0;      // DivisionByZeroError
echo 10 % 0;      // DivisionByZeroError

Har doim avval tekshiring yoki try/catch ishlating.

PHP

<?php
try {
  echo 10 / 0;
} catch (DivisionByZeroError $e) {
  echo "Xato: ", $e->getMessage();
}

Sonlarni formatlash

PHP

<?php
$narx = 1234567.891;

echo number_format($narx), "\n";
echo number_format($narx, 2), "\n";
echo number_format($narx, 0, ',', ' '), " so'm\n";

echo str_pad("7", 3, "0", STR_PAD_LEFT), "\n";
printf("%05.2f\n", 3.1);
printf("%+d %+d", 5, -5);

Amaliy misol — statistika

PHP

<?php
$ballar = [85, 92, 78, 65, 90, 88, 73];

$jami = array_sum($ballar);
$soni = count($ballar);
$ortacha = $jami / $soni;

sort($ballar);
$orta = $soni % 2 === 0
  ? ($ballar[$soni / 2 - 1] + $ballar[$soni / 2]) / 2
  : $ballar[intdiv($soni, 2)];

echo "Soni:      $soni\n";
echo "Jami:      $jami\n";
echo "O'rtacha:  ", round($ortacha, 2), "\n";
echo "Mediana:   $orta\n";
echo "Eng yuqori: ", max($ballar), "\n";
echo "Eng past:   ", min($ballar), "\n";

$otganlar = count(array_filter($ballar, fn($b) => $b >= 75));
echo "O'tganlar: $otganlar ta (", round($otganlar / $soni * 100), "%)";

Amaliy mashq

round, ceil va floor ni 2.5 da solishtiring;
0.1 + 0.2 === 0.3 ni tekshiring;
"42abc" ni (int) bilan o’giring — natija nima?
filter_var bilan xavfsiz tekshiruv yozing;
random_int bilan 5 ta tasodifiy son yarating;
narxdan 20% chegirma hisoblang va formatlang.

2- va 3-qadamlar sonlar bilan ishlashdagi ikki asosiy tuzoqni ko’rsatadi.

Qisqacha xulosa

PHP’da bo’lish odatda float qaytaradi; butun uchun intdiv.
round matematik, ceil yuqoriga, floor pastga yaxlitlaydi.
Kasr sonlarni === bilan solishtirmang; pulni tiyinda saqlang.
(int) "abc" jimgina 0 beradi — is_numeric/filter_var bilan tekshiring.
Xavfsiz tasodifiy son uchun random_int.
PHP 8 da nolga bo’lish DivisionByZeroError beradi.

Keyingi darsda sana va vaqt bilan ishlashni ko’ramiz.