R的XML到數據框

Question

我有下一個XML示例，我想要在R數據框中「列出」數據。最好的辦法是什麼，例如：如何配置xmlToDataFrame函數以URL開頭的工作？

<response> 
<area_name/> 
<bounding_box> 
<latitude_max>51.667389</latitude_max> 
<latitude_min>51.385262</latitude_min> 
<longitude_max>0.137236</longitude_max> 
<longitude_min>-0.34844</longitude_min> 
</bounding_box> 
<country>England</country> 
<county>London</county> 
<latitude>51.5263255</latitude> 
<listing> 
<agent_address>218a Brick Lane</agent_address> 
<agent_logo/> 
<agent_name>Salik & Co</agent_name> 
<agent_phone>020 3318 7059</agent_phone> 
<country/> 
<county>London</county> 
<description> 


Description: 
Salik & Co is offering this Commercial Freehold Property for sale on Wise Road, Stratford, London E15... Premises consists of: 
12 X 2 Bedroom Flat AS Following- 
* 2x Pent House With One Bath 
* 2x Flat With 2 Double Bed With 2 Bath 
* 8x Flat With 1 Bath 
* 4x Car Park 
* 4x floor with ground floor parking 
* Lift 
* Flat 11 & 13 Pent House with 500 sqft Terrace. 
* Flat 12 & Ground Floor shop sold for Long lease. Area Profile: 
Stratford is a place in the London Borough of Newham in East London. It will be the primary location of the 2012 Summer Olympics. The area is identified in the London Plan as one of 35 major centres in Greater London. Stratford has been a focus of regeneration for some years, and is the location of a number of major projects.... Property Location: 
Set only moments from the vibrant amenities of Stratford, Olympic park, Westfield Shopping centre. This modern 2 bed stunning flat offers contemporary accommodation with a private balcony, in a fabulous new eco building close to the green open spaces of East London 
Situated on Stratford High Street the property enjoys swift access into the fashionable bars, restaurants and boutiques of Stratford High Street. Transport links include Stratford (Central line, Jubilee Line and British Rail) which provide further link to district line. Price: 
Asking price £2.8 million. For further information contact: 
Ryan - 
Salik - 
Office - 
Email - 
Web - 

</description> 
<details_url>http://www.zoopla.co.uk/for-sale/details/4507257</details_url> 
<displayable_address>Wise Road, London</displayable_address> 
<image_caption/> 
<image_url> 
http://images.zoopla.co.uk/52367ed1b61a63c1b93f1ec0a70d39f83d590c74_354_255.jpg 
</image_url> 
<latitude>51.53477</latitude> 
<listing_id>4507257</listing_id> 
<listing_status>sale</listing_status> 
<longitude>-0.0045035</longitude> 
<num_bathrooms>0</num_bathrooms> 
<num_bedrooms>0</num_bedrooms> 
<num_floors>0</num_floors> 
<num_recepts>0</num_recepts> 
<outcode>E15</outcode> 
<post_town>London</post_town> 
<price>2800000</price> 
<price_change> 
<date>2010-04-27 00:42:05</date> 
<price>3000000</price> 
</price_change> 
<price_change> 
<date>2010-07-04 03:21:14</date> 
<price>2800000</price> 
</price_change> 
<property_type/> 
<street_name>Commercial Property</street_name> 
<thumbnail_url> 
http://images.zoopla.co.uk/52367ed1b61a63c1b93f1ec0a70d39f83d590c74_80_60.jpg 
</thumbnail_url> 
</listing> 
<listing> 
<agent_address>Rawlings House 2a Milner Street</agent_address> 
<agent_logo> 
http://static.zoopla.co.uk/zoopla_static_agent_logo_(29807).gif 
</agent_logo> 
<agent_name>Marsh & Parsons</agent_name> 
<agent_phone>020 3318 6922</agent_phone> 
<country/> 
<county>London</county> 
<description> 
A stunning, three bed mews house with spacious, roof terrace in a popular gated development off Milner Street and ideally located for the nearby amenities of South Kensington and Knightsbridge. A large reception room and a contemporary, open plan kitchen occupy the ground floor, while the first floor houses two double bedrooms and a modern family bathroom. An additional shower room can be found on the second floor which also has a substantial area suitable for a third bedroom and access to the sunny roof terrace. Located in the heart SW3's Brompton area, there is a multitude of local amenities available at Chelsea's popular King's Road and Sloane Street, while the shops, bars and restaurants of Brompton Road and Knightsbridge are easily reached. St. Catherine's Mews is ideally located for the Underground stations at both Sloane Square (Circle and District Lines) and South Kensington (Piccadilly, Circle and District Lines) while such a central location provides a number of convenient bus services. For transport links into and out of London the motorways can be accessed via the nearby A4.The property also has planning permission to extend the 2nd floor to encompass some of the roof terrace that would create greater internal square footage. 
</description> 
<details_url>http://www.zoopla.co.uk/for-sale/details/491528</details_url> 
<displayable_address>St Catherines Mews, London SW3</displayable_address> 
<floor_plan> 
http://content.zoopla.co.uk/5cb125b77de67eb6717bd8a2c74ba7edb6839959.jpg 
</floor_plan> 
<image_caption>Picture No.46</image_caption> 
<image_url> 
http://images.zoopla.co.uk/0867139d8bc2e2aac63056d75bbce1677de438c6_354_255.jpg 
</image_url> 
<latitude>51.493774</latitude> 
<listing_id>491528</listing_id> 
<listing_status>sale</listing_status> 
<longitude>-0.164762</longitude> 
<num_bathrooms>0</num_bathrooms> 
<num_bedrooms>2</num_bedrooms> 
<num_floors>0</num_floors> 
<num_recepts>0</num_recepts> 
<outcode>SW3</outcode> 
<post_town>London</post_town> 
<price>1500000</price> 
<price_change> 
<date>2009-05-16 01:40:29</date> 
<price>1350000</price> 
</price_change> 
<price_change> 
<date>2010-02-20 00:30:24</date> 
<price>1450000</price> 
</price_change> 
<price_change> 
<date>2011-02-12 00:31:53</date> 
<price>1500000</price> 
</price_change> 
<property_type>Town house</property_type> 
<street_name>London</street_name> 
<thumbnail_url> 
http://images.zoopla.co.uk/0867139d8bc2e2aac63056d75bbce1677de438c6_80_60.jpg 
</thumbnail_url> 
</listing> 
<listing> 
<agent_address>175 Putney High Street, Putney</agent_address> 
<agent_logo> 
http://static.zoopla.co.uk/zoopla_static_agent_logo_(47723).jpeg 
</agent_logo> 
<agent_name>Foxtons - Putney</agent_name> 
<agent_phone>020 3318 9160</agent_phone> 
<country/> 
<county>London</county> 
<description> 
A stunning four bedroomed house offering exceptionally spacious accommodation with stylish interior throughout. The property is arranged over four floors and comprises two good-sized reception rooms, generous 29' kitchen/dining room, four bedrooms (two with en suite), two bathrooms, two shower rooms, utility room, guest cloakroom, attractive garden and off-street parking. Akehurst Street is a quiet residential road located close to the green expanses of Richmond Park, and close to amenities in Roehampton with a greater selection of shops, bars and restaurants within easy reach in Putney. The area is well served by a number of local bus routes, while the nearby A3 provides motorists with a fast route into central London and to the South-West. 
</description> 
<details_url>http://www.zoopla.co.uk/for-sale/details/14226965</details_url> 
<displayable_address>Akehurst Street, London</displayable_address> 
<image_caption/> 
<image_url> 
http://images.zoopla.co.uk/5a24b05bff28865405aee72bcf4c46ae2ce299a4_354_255.jpg 
</image_url> 
<latitude>51.450905</latitude> 
<listing_id>14226965</listing_id> 
<listing_status>sale</listing_status> 
<longitude>-0.242762</longitude> 
<num_bathrooms>0</num_bathrooms> 
<num_bedrooms>4</num_bedrooms> 
<num_floors>0</num_floors> 
<num_recepts>0</num_recepts> 
<outcode>SW15</outcode> 
<post_town>London</post_town> 
<price>1499950</price> 
<property_type>Town house</property_type> 
<street_name>Akehurst Street</street_name> 
<thumbnail_url> 
http://images.zoopla.co.uk/5a24b05bff28865405aee72bcf4c46ae2ce299a4_80_60.jpg 
</thumbnail_url> 
</listing> 
<listing> 
<agent_address>55 Fulham Broadway, Fulham</agent_address> 
<agent_logo> 
http://static.zoopla.co.uk/zoopla_static_agent_logo_(47732).jpeg 
</agent_logo> 
<agent_name>Foxtons - Fulham</agent_name> 
<agent_phone>020 3318 6868</agent_phone> 
<country/> 
<county>London</county> 
<description> 
Located on a quiet residential street in Fulham, this great four bedroomed house offers spacious accommodation with loft conversion and south-facing flat roof. Arranged over three floors, the property comprises reception room with bay window, dining room, kitchen with space to dine and access to the garden, top floor master bedroom with en suite shower room, large second bedroom, two additional bedrooms, bathroom and outside store room. The property is situated on a tree-lined street, ideally located just moments from the local amenities on both Dawes Road and Lillie Road and is within easy reach of a more a comprehensive range of bars, shops and restaurants on nearby Fulham Broadway. The closest underground station is Fulham Broadway (District Line), providing convenient access to various central and greater London destinations. 
</description> 
<details_url>http://www.zoopla.co.uk/for-sale/details/14351415</details_url> 
<displayable_address>Prothero Road, London</displayable_address> 
<image_caption/> 
<image_url> 
http://images.zoopla.co.uk/a9d983b76018a07537de832224bb5174099c2758_354_255.jpg 
</image_url> 
<latitude>51.48186</latitude> 
<listing_id>14351415</listing_id> 
<listing_status>sale</listing_status> 
<longitude>-0.208447</longitude> 
<num_bathrooms>0</num_bathrooms> 
<num_bedrooms>4</num_bedrooms> 
<num_floors>0</num_floors> 
<num_recepts>0</num_recepts> 
<outcode>SW6</outcode> 
<post_town>London</post_town> 
<price>750000</price> 
<property_type>Town house</property_type> 
<street_name>Prothero Road</street_name> 
<thumbnail_url> 
http://images.zoopla.co.uk/a9d983b76018a07537de832224bb5174099c2758_80_60.jpg 
</thumbnail_url> 
</listing> 
<longitude>-0.105602</longitude> 
<postcode/> 
<result_count>76494</result_count> 
<street/> 
<town/> 
</response> 

謝謝

Answer 1

Dataframes要求輸入數據是 「矩形」。你顯然沒有這樣的數據安排。 R的列表數據類型更適合於這樣的事情。另一個問題似乎是在這個文件中出現的＆符號「&」。考慮到「&」是html中的轉義字符，這裏更安全的操作應該是將「&」替換爲「& amp」。如果將所有「&」更改爲「and」，則可以使用xmlToList（）來讀取它並創建相應的列表（但如果其中嵌入了有效的HTML，則可能會損壞其他文件）。

xmlToList(f)[grep("listing", names(xmlToList(f)))] 

（您需要提供一個URL）