XML XPath
XPath nima?
XPath — XSLT standartining asosiy tarkibiy qismi.
XPath’dan XML hujjatdagi elementlar va atributlar bo‘ylab harakatlanish uchun foydalanish mumkin.
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XPath yo‘l ifodalari
XPath XML hujjatdagi tugunlarni (node) yoki tugunlar to‘plamini (node-set) tanlash uchun yo‘l ifodalaridan foydalanadi. Bu yo‘l ifodalari an’anaviy kompyuter fayl tizimi bilan ishlaganda ko‘radigan ifodalaringizga juda o‘xshaydi.
XPath ifodalaridan JavaScript, Java, XML Schema, PHP, Python, C va C++ hamda boshqa ko‘plab tillarda foydalanish mumkin.
XPath XSLT’da ishlatiladi
XPath — XSLT standartining asosiy tarkibiy qismi.
XPath bo‘yicha bilimga ega bo‘lsangiz, XSL imkoniyatlaridan to‘liq foydalana olasiz.
XPath misoli
Biz quyidagi XML hujjatdan foydalanamiz:
<?xml version="1.0" encoding="UTF-8"?>
<bookstore>
<book category="cooking">
<title lang="en">Everyday Italian</title>
<author>Giada De Laurentiis</author>
<year>2005</year>
<price>30.00</price>
</book>
<book category="children">
<title lang="en">Harry Potter</title>
<author>J K. Rowling</author>
<year>2005</year>
<price>29.99</price>
</book>
<book category="web">
<title lang="en">XQuery Kick Start</title>
<author>James McGovern</author>
<author>Per Bothner</author>
<author>Kurt Cagle</author>
<author>James Linn</author>
<author>Vaidyanathan Nagarajan</author>
<year>2003</year>
<price>49.99</price>
</book>
<book category="web">
<title lang="en">Learning XML</title>
<author>Erik T. Ray</author>
<year>2003</year>
<price>39.95</price>
</book>
</bookstore>Quyidagi jadvalda ba’zi XPath ifodalari va ularning natijalarini keltirdik:
| XPath ifodasi | Natija |
|---|---|
| /bookstore/book[1] | bookstore elementining bolasi bo‘lgan birinchi book elementini tanlaydi |
| /bookstore/book[last()] | bookstore elementining bolasi bo‘lgan oxirgi book elementini tanlaydi |
| /bookstore/book[last()-1] | bookstore elementining bolasi bo‘lgan oxiridan bitta oldingi book elementini tanlaydi |
| /bookstore/book[position()<3] | bookstore elementining bolalari bo‘lgan dastlabki ikkita book elementini tanlaydi |
| //title[@lang] | lang nomli atributga ega barcha title elementlarini tanlaydi |
| //title[@lang='en'] | Qiymati "en" bo‘lgan "lang" atributiga ega barcha title elementlarini tanlaydi |
| /bookstore/book[price>35.00] | bookstore elementining qiymati 35.00 dan katta bo‘lgan price elementiga ega barcha book elementlarini tanlaydi |
| /bookstore/book[price>35.00]/title | bookstore elementining qiymati 35.00 dan katta bo‘lgan price elementiga ega book elementlaridagi barcha title elementlarini tanlaydi |
XPath darsligi
XPath haqida bizning XPath darsligimizda ancha ko‘proq narsalarni o‘rganasiz.
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