Masu samar da kayan aiki suna ba da karfinada da ma'amala mai karewa na aikin tafiya ta jerin batutuwa masu girma ta samar da ƙima ɗaya a ɗaya (sosai a hankali) ta amfani da kalmar yield, maimakon gina jeri gaba daya a ƙofar ƙwaƙwalwa a jiya. Suna da kyau sosai don batutuwa masu girma ko ɗakin sadarwa.
{
= [];
( = ; < ; ++) { [] = ; }
;
}
{
( = ; < ; ++) {
;
}
}
(() ) {
();
}
yield yana sa aiki zama mai samar da kayan aiki: yana samar da ƙima sosai a hankali, ɗaya a duk waje, yana tiyata jikinsa tsakanin su — sabili da ƙwaƙwalwa ya ci gaba daidai haba nawa ƙima yana samar.
function readLines(string $file): Generator {
$handle = fopen($file, 'r');
while (($line = fgets($handle)) !== false) {
yield $line; // yield one line at a time — never load the whole file
}
fclose($handle);
}
foreach (readLines('huge-10gb.csv') as $line) { // processes a 10GB file with tiny memory
process($line);
}
Karanta babbar fayil layin layi tare da mai samar da kayan aiki yana amfani da ƙwaƙwalwa da ma'amala — ba ya yiwuwa tare da file() (wanda ke shiqa cikakken fayil a cikin jeri).
function fetchRows(PDOStatement $stmt): Generator {
while ($row = $stmt->fetch()) {
yield $row['id'] => $row; // yield key => value, streaming DB rows
}
}
Masu samar da kayan aiki suna da kyau sosai don sadarwar sakamakon batutuwa — aiki da layi ɗaya a ɗaya maimakon shiqa babbar jeri sakamakon a ƙwaƙwalwa.
Masu samar da kayan aiki sune muhimmin aikin PHP don aiki mai karewa na batutuwa masu girma — kuma fahimtar su yana da daraja mai mahimmanci don gina aikace-aikace da suke tafiyar batutuwa a miski ba tare da kashe ƙwaƙwalwa ba.
Kaɓar gida da suke warware shi shi ne cewa gina jeri gaba daya na batutuwa masu girma (milyunanin bayani, layin manyan fayil, babbar sakamakon batutuwa) na iya ci daidai da ƙwaƙwalwa mai shuni da tashe aikace-aikace, daidai da haka masu samar da kayan aiki suna samar da ƙima sosai a hankali, ɗaya a ɗaya, yana tiyata ƙwaƙwalwa daidai haba yawa batutuwa.
Maɓuɓɓukan amfani masu tasiri sun fi mararaba da ma'ada: karanta manyan fayiloli layin layi (aiki tare da gigabytes CSV ko log tare da ƙwaƙwalwa kaɗan, ba ya yiwuwa tare da ayyuka da suke shiqa komai), sadarwar sakamakon batutuwa (tafiyar sakamakon buɗi babbar layi), da aiki tare da batutuwa masu girma ko har ma a ba tiyata.
Fahimtar yield, nazarin da hankali, kuma lokacin da za a ɗabi`u masu samar da kayan aiki (kowane lokacin da aka yanzu gina jeri masu girma a ƙwaƙwalwa) yana ba ka ƙarfi don rubutawa ko tsarin aiki da ake aiki ba tare da ƙwaƙwalwa mai yawa ba — karfi da ake buƙata a yau-yau a cikin ayyukan jeri, shigo/fita, samar da rahoto, da linin aiki.
Duk da cewa ba'a buƙata don batutuwa kaɗan, masu samar da kayan aiki sune ilimin da ya dace don PHP mara gaji da aiki tare da batutuwa mai yawa, yana bambanta masu aiki da zasu gina tsarin aiki mai girma batutuwa daga waɗanda aikace-aikacensa suka mutu ko jajira a ƙarƙashin batutuwa mai girma, yana sa shi da daraja mai mahimmanci akan waje-waje jiya don PHP da ke yi aiki da ƙwaƙwalwa.
Ɗakin karatu na tambayoyin hira na IT tare da amsoshi cikakke — daga Junior zuwa Senior.
Ba da Gudummawa