出于教育目的，我试图从this page开始逐渐使用Python and lxml，从电影名称开始。
从我到目前为止读到的关于lxml上的Python文档和XPath上的W3Schools来看，这段代码应该会让我看到列表中的所有电影片段：
from lxml import html
import requests
page = requests.get('http://www.rottentomatoes.com/browse/dvd-top-rentals/')
tree = html.fromstring(page.text)
movies = tree.xpath('//h3[@class="movieTitle"]/text()')
print movies
基本上，它应该为我提供文档中具有值为“movieTitle”的属性class的每个h3元素。在运行代码时，我只打印出一个空列表。
我无法弄清楚原因。
我自己尝试过，所以我跑了：
movies = tree.xpath('//h3[@class]/text()')
print movies
那么这个应该返回任何具有属性类的H3，但它会返回此列表：
['From RT Users Like You!', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ']
我尝试通过定位其类值（“noSpacing center”）来定位此列表中的第一个字符串，并成功返回此唯一字符串。所以我确信有一些我误解了lxml / XPath的工作原理。有人能指出我有用的方向吗？提前谢谢！
答案 0 :(得分：4)
有关http://www.rottentomatoes.com/browse/dvd-top-rentals/的信息未直接呈现在页面中，而是从 XMLHttpRequests 加载。
您正在寻找的API似乎是：
根据所选过滤器准备查询字符串。
因此，您必须向该端点发出请求（而不是您当前请求的URL）并解析JSON以提取所需数据。
您应该使用＆＃34; page＆＃34; GET变量以获得下一个变量。
cURL + jq 的示例：
➜ ~ curl -s http://d3biamo577v4eu.cloudfront.net/api/private/v1.0/m/list/find\?page\=1\&limit\=30\&type\=dvd-top-rentals\&services\=amazon%3Bamazon_prime%3Bflixster%3Bhbo_go%3Bitunes%3Bnetflix_iw%3Bvudu\&sortBy\=popularity | jq '.results[].title'
"Inside Out"
"Vacation"
"The End Of The Tour"
"She's Funny That Way"
"Best Of Enemies"
"Before We Go"
"Pixels"
"The Gift"
"Southpaw"
"Max"
"Jurassic World"
"San Andreas"
"Paper Towns"
"Dragon Ball Z: Resurrection 'F'"
"Testament Of Youth"
"The Wolfpack"
"Z For Zachariah"
"Tomorrowland"
"Terminator Genisys"
"Dope"
"The Gallows"
"Magic Mike XXL"
"Insidious: Chapter 3"
"Me and Earl and the Dying Girl"
"Particle Fever"
"Dark Places"
"What We Did on Our Holiday"
"Avengers: Age of Ultron"
"Spy"
"Poltergeist"
Python +请求的示例：
import json
import requests
URL = "http://d3biamo577v4eu.cloudfront.net/api/private/v1.0/m/list/find?page=2&limit=30&type=dvd-top-rentals&services=amazon%3Bamazon_prime%3Bflixster%3Bhbo_go%3Bitunes%3Bnetflix_iw%3Bvudu&sortBy=popularity"
response = requests.get(URL)
for movie in response.json()['results']:
movie_id = movie.get('id', None)
title = movie.get('title', None)
synopsis = movie.get('synopsis', None).encode('utf-8')
actors = ', '.join(movie.get('actors', None)).encode('utf-8')
tomato_score = movie.get('tomatoScore', None)
popcorn_score = movie.get('popcornScore', None)
mpaaRating = movie.get('mpaaRating', None)
runtime = movie.get('runtime', None)
print "Id: {}".format(movie_id)
print "Title: {}".format(title)
print "Synopsis: {}".format(synopsis)
print "Actors: {}".format(actors)
print "Rating: {}".format(mpaaRating)
print "Runtime: {}".format(runtime)
print "Scoring:"
print "Tomato score: {}".format(tomato_score)
print "PopCorn score: {}".format(popcorn_score)
print ""
输出：
Id: 771306118
Title: Inside Out
Synopsis: Inventive, gorgeously animated, and powerfully moving, Inside Out is another outstanding addition to the Pixar library of modern animated classics.
Actors: Amy Poehler, Bill Hader, Lewis Black
Rating: PG
Runtime: 1 hr. 34 min.
Scoring:
Tomato score: 98
PopCorn score: 90
Id: 771312080
Title: Vacation
Synopsis: Borrowing a basic storyline from the film that inspired it but forgetting the charm, wit, and heart, Vacation is yet another nostalgia-driven retread that misses the mark.
Actors: Ed Helms, Christina Applegate, Leslie Mann
Rating: R
Runtime: 1 hr. 39 min.
Scoring:
Tomato score: 26
PopCorn score: 53
Id: 771411936
Title: The End Of The Tour
Synopsis: Brilliantly performed and smartly unconventional, The End of the Tour pays fitting tribute to a singular talent while offering profoundly poignant observations on the human condition.
Actors: Jesse Eisenberg, Jason Segel, Anna Chlumsky
Rating: R
Runtime: 1 hr. 45 min.
Scoring:
Tomato score: 92
PopCorn score: 88
Id: 771402562
Title: She's Funny That Way
Synopsis: She's Funny That Way is an affectionate, talent-filled throwback to screwball comedies of old -- which makes it even more frustrating that the laughs are disappointingly few and far between.
Actors: Imogen Poots, Owen Wilson, Jennifer Aniston
Rating: R
Runtime: 1 hr. 33 min.
Scoring:
Tomato score: 38
PopCorn score: 38
Id: 771412027
Title: Best Of Enemies
Synopsis: Smart, fascinating, and funny, Best of Enemies takes a penetrating -- and wildly entertaining -- look back at the dawn of pundit politics.
Actors: Dick Cavett, Gore Vidal, John Lithgow
Rating: R
Runtime: 1 hr. 27 min.
Scoring:
Tomato score: 94
PopCorn score: 94
Id: 771387770
Title: Before We Go
Synopsis: BEFORE WE GO, the directorial debut of Chris Evans, follows the journey of two strangers stuck in New York City for the night. Starting as convenient acquaintances, the two soon grow into each other's most trusted confidants when a night of unexpected adventure forces them to confront their fears and take control of their lives. (C) Radius-TWC
Actors: Alice Eve, Chris Evans, Daniel Spink
Rating: PG-13
Runtime: 1 hr. 29 min.
Scoring:
Tomato score: 25
PopCorn score: 64
Id: 771263974
Title: Pixels
Synopsis: Much like the worst arcade games from the era that inspired it, Pixels has little replay value and is hardly worth a quarter.
Actors: Adam Sandler, Peter Dinklage, Kevin James
Rating: PG-13
Runtime: 1 hr. 46 min.
Scoring:
Tomato score: 17
PopCorn score: 51
Id: 771415974
Title: The Gift
Synopsis: The Gift is wickedly smart and playfully subversive, challenging the audience's expectations while leaving them leaning on the edges of their seats.
Actors: Jason Bateman, Rebecca Hall, Joel Edgerton
Rating: R
Runtime: 1 hr. 48 min.
Scoring:
Tomato score: 93
PopCorn score: 78
Id: 771258788
Title: Southpaw
Synopsis: Jake Gyllenhaal delivers an impressively committed performance, but Southpaw beats it down with a dispiriting drama that pummels viewers with genre clichés.
Actors: Jake Gyllenhaal, Forest Whitaker, Rachel McAdams
Rating: R
Runtime: 2 hr. 3 min.
Scoring:
Tomato score: 59
PopCorn score: 79
Id: 771379965
Title: Max
Synopsis: Max has good intentions and tries to hearken back to classic family-friendly features, but its disjointed, manipulative plot overwhelms the efforts of its talented human and canine stars.
Actors: Josh Wiggins, Lauren Graham, Thomas Haden Church
Rating: PG
Runtime: 1 hr. 51 min.
Scoring:
Tomato score: 35
PopCorn score: 73
Id: 771324839
Title: Jurassic World
Synopsis: Jurassic World can't match the original for sheer inventiveness and impact, but it works in its own right as an entertaining -- and visually dazzling -- popcorn thriller.
Actors: Chris Pratt, Bryce Dallas Howard, Vincent D'Onofrio
Rating: PG-13
Runtime: 2 hr. 3 min.
Scoring:
Tomato score: 71
PopCorn score: 80
Id: 771374432
Title: San Andreas
Synopsis: San Andreas has a great cast and outstanding special effects, but amidst all the senses-shattering destruction, the movie's characters and plot prove less than structurally sound.
Actors: Dwayne "The Rock" Johnson, Carla Gugino, Alexandra Daddario
Rating: PG-13
Runtime: 1 hr. 54 min.
Scoring:
Tomato score: 50
PopCorn score: 56
Id: 771385882
Title: Paper Towns
Synopsis: Paper Towns isn't as deep or moving as it wants to be, yet it's still earnest, well-acted, and thoughtful enough to earn a place in the hearts of teen filmgoers of all ages.
Actors: Nat Wolff, Cara Delevingne, Halston Sage
Rating: PG-13
Runtime: 1 hr. 49 min.
Scoring:
Tomato score: 55
PopCorn score: 53
Id: 771419940
Title: Dragon Ball Z: Resurrection 'F'
Synopsis: Even the complete obliteration of his physical form can't stop the galaxy's most evil overlord. After years in spiritual purgatory, Frieza has been resurrected and plans to take his revenge on the Z-Fighters of Earth. Facing off against Frieza's powerful new form, and his army of 1,000 soldiers, Goku and Vegeta must reach new levels of strength in order to protect Earth from their vengeful nemesis.
Actors: Koichi Yamadera, Todd Haberkorn, Sean Schemmel
Rating: Unrated
Runtime: 1 hr. 33 min.
Scoring:
Tomato score: 75
PopCorn score: 86
Id: 771385848
Title: Testament Of Youth
Synopsis: Testament of Youth is well-acted and beautifully filmed, adding up to an enriching if not adventurous experience for fans of British period dramas.
Actors: Alicia Vikander, Kit Harington, Dominic West
Rating: PG-13
Runtime: 2 hr. 9 min.
Scoring:
Tomato score: 81
PopCorn score: 79
Id: 771412119
Title: The Wolfpack
Synopsis: Offering a unique look at modern fears and our fascination with film, The Wolfpack is a fascinating -- and ultimately haunting -- urban fable.
Actors: Visnu Angulo, Susanne Angulo, Oscar Angulo
Rating: R
Runtime: 1 hr. 20 min.
Scoring:
Tomato score: 84
PopCorn score: 73
Id: 771408592
Title: Z For Zachariah
Synopsis: Z for Zachariah wrings compelling drama out of its simplistic premise -- albeit at a pace that may test the patience of less contemplative viewers.
Actors: Chiwetel Ejiofor, Chris Pine, Margot Robbie
Rating: PG-13
Runtime: 1 hr. 35 min.
Scoring:
Tomato score: 77
PopCorn score: 47
Id: 771306778
Title: Tomorrowland
Synopsis: Ambitious and visually stunning, Tomorrowland is unfortunately weighted down by uneven storytelling.
Actors: George Clooney, Hugh Laurie, Brittany Robertson
Rating: PG
Runtime: 1 hr. 47 min.
Scoring:
Tomato score: 50
PopCorn score: 52
Id: 771359910
Title: Terminator Genisys
Synopsis: Mired in its muddled mythology, Terminator: Genisys is a lurching retread that lacks the thematic depth, conceptual intelligence, or visual thrills that launched this once-mighty franchise.
Actors: Emilia Clarke, Jason Clarke, Jai Courtney
Rating: PG-13
Runtime: 1 hr. 59 min.
Scoring:
Tomato score: 26
PopCorn score: 59
Id: 771412133
Title: Dope
Synopsis: Featuring a starmaking performance from Shameik Moore and a refreshingly original point of view from writer-director Rick Famuyiwa, Dope is smart, insightful entertainment.
Actors: Shameik Moore, Kiersey Clemons, Tony Revolori
Rating: R
Runtime: 1 hr. 55 min.
Scoring:
Tomato score: 87
PopCorn score: 85
Id: 771417481
Title: The Gallows
Synopsis: Narratively contrived and visually a mess, The Gallows sends viewers on a shaky tumble to the bottom of the found-footage horror barrel.
Actors: Cassidy Gifford, Pfeifer Brown, Ryan Shoos
Rating: R
Runtime: 1 hr. 27 min.
Scoring:
Tomato score: 16
PopCorn score: 25
Id: 771378808
Title: Magic Mike XXL
Synopsis: Magic Mike XXL has enough narrative thrust and beefy charm to deliver another helping of well-oiled entertainment, even if this sequel isn't quite as pleasurable as its predecessor.
Actors: Channing Tatum, Matt Bomer, Joe Manganiello
Rating: R
Runtime: 1 hr. 55 min.
Scoring:
Tomato score: 62
PopCorn score: 61
Id: 771375494
Title: Insidious: Chapter 3
Synopsis: Insidious: Chapter 3 isn't as terrifying as the original, although it boasts surprising thematic depth and is enlivened by another fine performance from Lin Shaye.
Actors: Dermot Mulroney, Stefanie Scott, Angus Sampson
Rating: PG-13
Runtime: 1 hr. 37 min.
Scoring:
Tomato score: 60
PopCorn score: 54
Id: 771412075
Title: Me and Earl and the Dying Girl
Synopsis: Beautifully scripted and perfectly cast, Me & Earl & the Dying Girl is a coming-of-age movie with uncommon charm and insight.
Actors: Thomas Mann, R.J. Cyler, Olivia Cooke
Rating: PG-13
Runtime: 1 hr. 44 min.
Scoring:
Tomato score: 81
PopCorn score: 88
Id: 771364355
Title: Particle Fever
Synopsis: The concepts behind its heady subject matter may fly over the heads of most viewers, but Particle Fever presents it in such a way that even the least science-inclined viewers will find themselves enraptured.
Actors: Savas Dimopoulos, Nima Arkani-Hamed, Fabiola Gianotti
Rating: Unrated
Runtime: 1 hr. 39 min.
Scoring:
Tomato score: 95
PopCorn score: 84
Id: 771362649
Title: Dark Places
Synopsis: 25 years after testifying against her brother as the person responsible for massacring her entire family, a haunted woman (Charlize Theron) is approached by a secret society that specializes in complex, unsolved cases. Nicholas Hoult, Corey Stoll, and Chloe Moretz co-star in this Mandalay Pictures thriller directed by Gilles Paquet-Brenner, and based on the novel by Gillian Flynn. ~ Jason Buchanan, Rovi
Actors: Charlize Theron, Nicholas Hoult, Corey Stoll
Rating: R
Runtime: 1 hr. 54 min.
Scoring:
Tomato score: 26
PopCorn score: 35
Id: 771357112
Title: What We Did on Our Holiday
Synopsis: Witty and well-cast, What We Did on Our Holiday injects unlikely laughs into a story dealing with dark, difficult themes.
Actors: Rosamund Pike, David Tennant, Billy Connolly
Rating: PG-13
Runtime: 1 hr. 35 min.
Scoring:
Tomato score: 73
PopCorn score: 73
Id: 771313962
Title: Avengers: Age of Ultron
Synopsis: Exuberant and eye-popping, Avengers: Age of Ultron serves as an overstuffed but mostly satisfying sequel, reuniting its predecessor's unwieldy cast with a few new additions and a worthy foe.
Actors: Robert Downey Jr., Chris Evans, Mark Ruffalo
Rating: PG-13
Runtime: 2 hr. 21 min.
Scoring:
Tomato score: 74
PopCorn score: 85
Id: 771361497
Title: Spy
Synopsis: Simultaneously broad and progressive, Spy offers further proof that Melissa McCarthy and writer-director Paul Feig bring out the best in one another -- and delivers scores of belly laughs along the way.
Actors: Melissa McCarthy, Jason Statham, Rose Byrne
Rating: R
Runtime: 1 hr. 57 min.
Scoring:
Tomato score: 93
PopCorn score: 81
Id: 770799339
Title: Poltergeist
Synopsis: Paying competent homage without adding anything of real value to the original Poltergeist, this remake proves just as ephemeral (but half as haunting) as its titular spirit.
Actors: Sam Rockwell, Rosemarie DeWitt, Kyle Catlett
Rating: PG-13
Runtime: 1 hr. 33 min.
Scoring:
Tomato score: 31
PopCorn score: 23
Id: 771370467
Title: Entourage
Synopsis: Entourage retains many elements of the HBO series, but feels less like a film than a particularly shallow, cameo-studded extended episode of the show.
Actors: Jeremy Piven, Adrian Grenier, Kevin Dillon
Rating: R
Runtime: 1 hr. 45 min.
Scoring:
Tomato score: 32
PopCorn score: 64
Id: 771412037
Title: Cop Car
Synopsis: Cop Car boasts a terrific premise and a grimly gripping opening act -- and for some viewers, that will be enough to compensate for the movie's uneven denouement.
Actors: Kevin Bacon, Shea Whigham, Camryn Manheim
Rating: R
Runtime: 1 hr. 26 min.
Scoring:
Tomato score: 79
PopCorn score: 52
Id: 771412114
Title: Unexpected
Synopsis: Unexpected proves a thoughtful and well-acted -- if somewhat mild -- look at worthy, thought-provoking themes.
Actors: Anders Holm, Cobie Smulders, Gail Bean
Rating: R
Runtime: 1 hr. 30 min.
Scoring:
Tomato score: 67
PopCorn score: 49
Id: 771356696
Title: Pitch Perfect 2
Synopsis: Pitch Perfect 2 sings in sweet comedic harmony, even if it doesn't hit quite as many high notes as its predecessor.
Actors: Anna Kendrick, Rebel Wilson, Brittany Snow
Rating: PG-13
Runtime: 1 hr. 54 min.
Scoring:
Tomato score: 66
PopCorn score: 67
Id: 771354922
Title: Furious 7
Synopsis: Serving up a fresh round of over-the-top thrills while adding unexpected dramatic heft, Furious 7 keeps the franchise moving in more ways than one.
Actors: Vin Diesel, Paul Walker, Jason Statham
Rating: PG-13
Runtime: 2 hr. 20 min.
Scoring:
Tomato score: 81
PopCorn score: 84
Id: 771270966
Title: Cinderella
Synopsis: Refreshingly traditional in a revisionist era, Kenneth Branagh's Cinderella proves Disney hasn't lost any of its old-fashioned magic.
Actors: Lily James, Cate Blanchett, Richard Madden
Rating: PG
Runtime: 1 hr. 45 min.
Scoring:
Tomato score: 85
PopCorn score: 79
Id: 771359745
Title: Love & Mercy
Synopsis: As unconventional and unwieldy as the life and legacy it honors, Love & Mercy should prove moving for Brian Wilson fans while still satisfying neophytes.
Actors: Paul Dano, Elizabeth Banks, Brett Davern
Rating: PG-13
Runtime: 2 hr.
Scoring:
Tomato score: 89
PopCorn score: 86
Id: 771378525
Title: Monkey Kingdom
Synopsis: Monkey Kingdom's breathtaking footage of primates in the wild is likely to please animal lovers of all ages.
Actors: Tina Fey
Rating: G
Runtime: 1 hr. 25 min.
Scoring:
Tomato score: 94
PopCorn score: 77
Id: 771412081
Title: The Overnight
Synopsis: Witty and unpredictable, The Overnight benefits from writer-director Patrick Brice's sure-handed touch and strong performances from a talented cast.
Actors: Adam Scott, Taylor Schilling, Jason Schwartzman
Rating: R
Runtime: 1 hr. 20 min.
Scoring:
Tomato score: 82
PopCorn score: 60
Id: 771374337
Title: Diplomacy
Synopsis: For filmgoers who value character development and smart dialogue over plot, Diplomacy yields rich, powerfully acted rewards.
Actors: André Dussollier, Niels Arestrup, Robert Stadlober
Rating: Unrated
Runtime: 1 hr. 25 min.
Scoring:
Tomato score: 93
PopCorn score: 80
Id: 771373149
Title: The Age of Adaline
Synopsis: The Age of Adaline ruminates on mortality less compellingly than similarly themed films, but is set apart by memorable performances from Blake Lively and Harrison Ford.
Actors: Blake Lively, Michiel Huisman, Harrison Ford
Rating: PG-13
Runtime: 1 hr. 49 min.
Scoring:
Tomato score: 54
PopCorn score: 67
Id: 771028170
Title: Mad Max: Fury Road
Synopsis: With exhilarating action and a surprising amount of narrative heft, Mad Max: Fury Road brings George Miller's post-apocalyptic franchise roaring vigorously back to life.
Actors: Tom Hardy, Charlize Theron, Nicholas Hoult
Rating: R
Runtime: 2 hr.
Scoring:
Tomato score: 97
PopCorn score: 87
Id: 770683518
Title: I'll See You in My Dreams
Synopsis: I'll See You in My Dreams would be worth watching even if Blythe Danner's central performance was all it had going for it, but this thoughtful drama satisfies on multiple levels.
Actors: Blythe Danner, Martin Starr, Sam Elliott
Rating: PG-13
Runtime: 1 hr. 35 min.
Scoring:
Tomato score: 94
PopCorn score: 70
Id: 771387966
Title: Good Kill
Synopsis: Thought-provoking, timely, and anchored by a strong performance from Ethan Hawke, Good Kill is a modern war movie with a troubled conscience.
Actors: Ethan Hawke, January Jones, Zoë Kravitz
Rating: R
Runtime: 1 hr. 43 min.
Scoring:
Tomato score: 76
PopCorn score: 49
Id: 771377895
Title: Dior and I
Synopsis: Dior and I will obviously appeal to fashion fans, but this beautifully tailored documentary may draw in even the least sartorially inclined.
Actors: Omar Berrada, Marion Cotillard, Anna Wintour
Rating: R
Runtime: 1 hr. 30 min.
Scoring:
Tomato score: 82
PopCorn score: 80
Id: 771387025
Title: Glen Campbell: I'll Be Me
Synopsis: The heartrendingly honest Glen Campbell: I'll Be Me offers a window into Alzheimer's that should prove powerful viewing for Campbell fans and novices alike.
Actors: Bruce Springsteen, Bill Clinton, Paul McCartney
Rating: PG
Runtime: 1 hr. 56 min.
Scoring:
Tomato score: 100
PopCorn score: 91
Id: 771378194
Title: Boulevard
Synopsis: Boulevard features a richly layered performance from Robin Williams, but that may be this dour drama's sole distinctive feature.
Actors: Robin Williams, Kathy Baker, Roberto Aguire
Rating: R
Runtime: 1 hr. 28 min.
Scoring:
Tomato score: 51
PopCorn score: 33
Id: 770804151
Title: About Elly
Synopsis: About Elly offers viewers performances as powerful as its thought-provoking ideas, and adds another strong entry to Asghar Farhadi's impressive filmography.
Actors: Golshifteh Farahani, Taraneh Alidoosti, Taraneh Alidousti
Rating: Unrated
Runtime: 1 hr. 59 min.
Scoring:
Tomato score: 97
PopCorn score: 86
答案 1 :(得分：3)
使用selenium是另一种等待页面完全加载的方式（即包括所有JavaScript操作）。您不必使用Firefox，如果不需要显示实际网站，您可以使用其他浏览器或Phantom JS之类的无头浏览器。
from lxml import html
from selenium import webdriver
browser = webdriver.Firefox()
browser.get("http://www.rottentomatoes.com/browse/dvd-top-rentals/")
tree = html.fromstring(browser.page_source)
movies = tree.xpath('//h3[@class="movieTitle"]/text()')
browser.close()
print movies
输出：
['Inside Out', 'Vacation', 'The End Of The Tour', "She's Funny That Way", 'Best Of Enemies', 'Before We Go', 'Pixels', 'The Gift', 'Southpaw', 'Max', 'Jurassic World', 'San Andreas
', 'Paper Towns', "Dragon Ball Z: Resurrection 'F'", 'Testament Of Youth', 'The Wolfpack', 'Z For Zachariah', 'Tomorrowland', 'Terminator Genisys', 'Dope', 'The Gallows', 'Magic Mi
ke XXL', 'Insidious: Chapter 3', 'Me and Earl and the Dying Girl', 'Particle Fever', 'Dark Places', 'What We Did on Our Holiday', 'Avengers: Age of Ultron', 'Spy', 'Poltergeist']