Novice yanar gizo shirye-shirye PHP: kirtani tsawon

Duk wani kai mutunta yanar gizo shirye-shiryen dole san harshen PHP, wanda za a iya amfani da su haifar da shafukan yanar gizo. Wannan harshen dogara ne a kan C da kuma C ++, sabili da haka shi yana da yawa Tsarin musamman ga harshe. Alal misali, a cikin PHP tsawon na kirtani koma da aiki tare da wannan sunan kamar yadda a cikin C. Wannan labarin yayi Magana game da Lines, kazalika da yadda ake gudanar da za a iya yi tare da su.

Amma kafin mu yi magana game da siffofin da zai ba da asali definition. Kirtani - a jerin haruffa, kowanne daga abin da daukan daidai da daya byte. Saboda haka, PHP yana goyan bayan da 256 characters. Daga wannan Azancin shi ya bi cewa Unicode goyon baya ga wannan harshe ya bace - saboda Unicode haruffa yafi.

Abin da kirtani ayyukan can a PHP? A kirtani tsawon, su concatenation (connection), dawo da hali code, kuma mataimakin versa - mafi sauki misalai. Akwai kuma mafi hadaddun - substring search, hashing, invert. Kuma akwai kamar cire tags, abin kõyi daidai da, raba cikin substrings amfani delimiter ... ku suna da shi! Saboda haka, za mu tattauna ne ya fi kowa da kuma amfani mãsu girmansu.

A farko, kuma sau da yawa amfani aiki a PHP - kirtani tsawon. An kira strlen, kazalika da siga daukan guda jerin haruffa. Yana da sauki.

$ Foo = "foo".

$ Bar = strlen ($ foo). // $ mashaya ne daidai da uku

?>

A PHP kirtani tsawon iya zama daidai a sifili. Wannan layin da aka kira komai.

Wadannan aiki - concatenation ko ci. Kawai sa, shi ne a biyu-line sa daya.

$ Foo = "Hello".

$ Bar = "Duniya".

$ Baz = concat ($ foo, $ mashaya).

amsa kuwa $ Baz. // jimloli "Hello duniya!"

?>

Akwai biyu kishiya ayyuka da aiki tare da mutum haruffa. Ord - dawo da hali code, kuma Tar - kayyade hali code.

$ Foo = "q".

$ Bar = Ord ($ foo). // $ mashaya ne, sunã daidaita da 113

$ Baz = Tar ($ mashaya). // $ Baz ne "q"

?>

Ba a ma maganar game da wani ban sha'awa alama - kwanan wata. A PHP kirtani za a iya amfani azaman samfuri ga fitarwa lokaci. Alal misali, idan canja wuri zuwa ranar line "H: m: s" da kuma fitarwa sakamakon, allon zai nuna yanzu lokaci na uwar garke, rabu da wani ciwon, misali, "11:08:34".

Yanzu la'akari da fashe aiki. Yana tsãgewar ƙwãyar kirtani cikin abubuwa, idan akai la'akari da iyakar kowane Said alama. Yana sauti kyawawan rikitarwa, amma shi ne ainihin quite m. Alal misali, akwai wani layi "tushen | 12: 56: 49 | dabaran". Sa'an nan za mu iya rubuta:

$ Foo = fashe ( "tushen | 12: 56: 49 | dabaran", "|");

A sakamakon haka, tsararru $ foo zai dauke da uku abubuwa - "tushen", "12:56:49", "dabaran". Idan aiki kira ba saka a SEPARATOR, da tsoho shi za a yi la'akari da wani blank. Akwai daya tilas siga - matsakaicin adadin kasaftawa substring.

Wadannan aiki kawar da layin HTML-tags. strip_tags ta kira. Kamar yadda da The fashe aiki, shi yana da wani tilas biyu siga - jerin tags cewa kana so ka bar.

Simple ayyuka - concatenation, substring search, da kirtani tsawon - da PHP fassara azumi isa. Amma da search aiki a kan wani samfuri ko share tags za a iya yi na dogon lokaci. Saboda haka, shirye-shirye bukatar zama gwani, Ganin cewa ta aiwatar daukan lokaci. Al'ada rubutun dole ne a gudu a kalla 10 seconds, sa'an nan kana so ka nuna a kalla kashi na wani shafin yanar gizo, ko wani mai amfani da shi zai je. Amma yawanci Web aikace-aikace gudu da sauri, saboda PHP code shi ne hukuncin kisa a kan uwar garke da browser daukan kafa a kan tushen da rubutun page cewa ƙarasa da PHP-script.