我试图提取＆＃39; alt＆＃39;下面代码块中图片的标记，周围div的类是＆＃39; onIcon＆＃39;。（示例= Modelcontract或Kabeltelevisie）
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<tr class="odd"><td><div class="roomdetail_icon onIcon Modelcontract"><a href="/nl/modelcontract"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_modelcontract_on.png" alt="Modelcontract" /></a></div></td><td><div class="roomdetail_icon onIcon Kamer"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_room_on.png" alt="Kamer" /></div></td><td><div class="roomdetail_icon offIcon Studio"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_studio_off.png" alt="Studio" /></div></td><td><div class="roomdetail_icon offIcon Appartement"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_apartment_off.png" alt="Appartement" /></div></td><td><div class="roomdetail_icon onIcon Internet"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_internet_on.png" alt="Internet" /></div></td> </tr>
<tr class="even"><td><div class="roomdetail_icon onIcon Kabeltelevisie"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_cable_tv_on.png" alt="Kabeltelevisie" /></div></td><td><div class="roomdetail_icon onIcon Gemeenschappelijke leefruimte"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_shared_living_space_on.png" alt="Gemeenschappelijke leefruimte" /></div></td><td><div class="roomdetail_icon onIcon Tuin/terras"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_garden_on.png" alt="Tuin/terras" /></div></td><td><div class="roomdetail_icon onIcon Fietsenstalling"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_bicycle_shed_on.png" alt="Fietsenstalling" /></div></td><td><div class="roomdetail_icon offIcon Beddengoed"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_bedding_off.png" alt="Beddengoed" /></div></td> </tr>
<tr class="odd"><td><div class="roomdetail_icon onIcon Keukengerei"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_kitchen_utensils_on.png" alt="Keukengerei" /></div></td><td><div class="roomdetail_icon offIcon Muziekinstrumenten toegelaten"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_musical_instruments_allowed_off.png" alt="Muziekinstrumenten toegelaten" /></div></td><td><div class="roomdetail_icon offIcon Roken niet toegelaten"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_smoking_allowed_off.png" alt="Roken niet toegelaten" /></div></td><td><div class="roomdetail_icon offIcon Huisdieren wel/niet toegelaten"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_animals_allowed_off.png" alt="Huisdieren wel/niet toegelaten" /></div></td><td><div class="roomdetail_icon offIcon Bemeubeld"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_furnished_off.png" alt="Bemeubeld" /></div></td> </tr>
<tr class="even"><td><div class="roomdetail_icon offIcon Toegankelijk voor rolstoelgebruikers"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_wheelchair_accssible_off.png" alt="Toegankelijk voor rolstoelgebruikers" /></div></td><td><div class="roomdetail_icon offIcon Geschikt voor allergiepatienten"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_allergies_off.png" alt="Geschikt voor allergiepatienten" /></div></td><td><div class="roomdetail_icon offIcon Verhuur aan niet-studenten"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_non_students_off.png" alt="Verhuur aan niet-studenten" /></div></td><td><div class="roomdetail_icon offIcon Straatkant"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_street_off.png" alt="Straatkant" /></div></td><td><div class="roomdetail_icon onIcon Niet aan straatkant"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_notstreet_on.png" alt="Niet aan straatkant" /></div></td> </tr>
<tr class="odd"><td><div class="roomdetail_icon onIcon Building regulations"><img src="/sites/all/themes/kotweb/images/icons/grid/grid_building_regulations_on.png" alt="Building regulations" /></div></td> </tr>
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我在Python中使用XPath并得到了以下查询：
'features': response.xpath("//div[@class='onIcon']//img/@alt").extract()
不幸的是，这会返回一个空数组（[]）。
我已经坚持了很长一段时间了：我做错了什么？
亲切的问候， 托马斯
答案 0 :(得分：0)
.babelrc该类的值为response.xpath("//div[@class[contains(., 'onIcon')]]//img/@alt")
，而不只是roomdetail_icon onIcon Modelcontract，您应该使用onIcon函数
contains表示当前上下文节点（@class）。
出：
.每次执行['Modelcontract',
'Kamer',
'Internet',
'Kabeltelevisie',
'Gemeenschappelijke leefruimte',
'Tuin/terras',
'Fietsenstalling',
'Keukengerei',
'Niet aan straatkant',
'Building regulations']
时，xpath都会执行以下步骤：
[@class='onIcon']，因此它会将'onIcon'转换为字符串，在这种情况下，可以比较这两者。@class转换为字符串，有一个@class函数，string()将返回类的值string(@class) roomdetail_icon onIcon Modelcontract