1
我完全沉迷於這一個。無法賦值給變量：未定義的方法`[]'爲零：NilClass（NoMethodError）
我有以下代碼：
puts block.at_xpath("*/img")["width"].to_i
但是當我將其更改爲
width = block.at_xpath("*/img")["width"].to_i
我得到這個錯誤：當我有看跌期權在那裏
NokogiriTUT.rb:70:in `blockProcessor': undefined method `[]' for nil:NilClass (NoMethodError)
它返回預期值。
更新：
def blockProcessor(block)
header = block.xpath('td[@class="default"]/*/span[@class="comhead"]')
array = header.text.split
if array[0] != nil #checks to make sure we aren't at the top of the parent list
### Date and Time ###
if array[2] == 'hours' || array[2] == 'minutes'
date = Time.now
else
days = (array[1].to_i * 24 * 60 * 60)
date = Time.now - days
end
##Get Comment##
comment = block.at_xpath('*/span[@class="comment"]')
hash = comment.text.hash
#puts hash
##Manage Parent Here##
width = block.at_xpath("*/img")["width"].to_i
prevlevel = @parent_array[@parent_array.length-1][1]
if width == 0 #has parents
parentURL = header.xpath('a[@href][3]').to_s
parentURL = parentURL[17..23]
parentURL = "http://news.ycombinator.com/item?id=#{parentURL}"
parentdoc = Nokogiri::HTML(open(parentURL))
a = parentdoc.at_xpath("//html/body/center/table/tr[3]/td/table/tr")
nodeparent = blockProcessor(a)
@parent_array = []
node = [hash, width, nodeparent] #id, level, parent
@parent_array.push node
elsif width > prevlevel
nodeparent = @parent_array[@parent_array.length-1][0]
node = [hash, width, nodeparent]
@parent_array.push node
elsif width == prevlevel
nodeparent = @parent_array[@parent_array.length-1][2]
node = [hash, width, nodeparent]
@parent_array.push node
elsif width < prevlevel
until prevlevel == w do
@parent_array.pop
prevlevel = @parent_array[@parent_array.length-1][1]
end
nodeparent = @parent_array[@parent_array.length-1][2]
node = [hash, width, nodeparent]
@parent_array.push node
end
puts "Author: #{array[0]} with hash #{hash} with parent: #{nodeparent}"
##Handles Any Parents of Existing Comments ##
return hash
end
end
end
這裏是它作用於塊。
<tr>
<td><img src="http://ycombinator.com/images/s.gif" height="1" width="0"></td>
<td valign="top"><center>
<a id="up_3004849" href="vote?for=3004849&dir=up&whence=%2f%78%3f%66%6e%69%64%3d%34%6b%56%68%71%6f%52%4d%38%44"><img src="http://ycombinator.com/images/grayarrow.gif" border="0" vspace="3" hspace="2"></a><span id="down_3004849"></span>
</center></td>
<td class="default">
<div style="margin-top:2px; margin-bottom:-10px; "><span class="comhead"><a href="user?id=patio11">patio11</a> 12 days ago | <a href="item?id=3004849">link</a> | <a href="item?id=3004793">parent</a> | on: <a href="item?id=3004471">Ask HN: What % of your job interviewees pass FizzB...</a></span></div>
<br><span class="comment"><font color="#000000">Every time FizzBuzz problems come up among engineers, people race to solve them and post their answers, then compete to see who can write increasingly more nifty answers for a question which does not seek niftiness at all.<p>I'm all for intellectual gamesmanship, but these are our professional equivalent of a doctor being asked to identify the difference between blood and water. You can do it. <i>We know</i>. Demonstrating that you can do it is not the point of the exercise. We do it to have a cheap-to-administer test to exclude people-who-cannot-actually-program-despite-previous-job-titles from the expensive portions of the hiring process.</p></font></span><p><font size="1"><u><a href="reply?id=3004849&whence=%2f%78%3f%66%6e%69%64%3d%34%6b%56%68%71%6f%52%4d%38%44">reply</a></u></font></p>
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您是否在調用'at_xpath'之前嘗試添加'puts block'。也許你有一個副作用，正在改變'塊' – knut
@ knut，我只是再檢查一下，那是有效的。另外，投入給我我期望和想要的價值是奇怪的。我想要做的就是將它分配給一個變量。 –
「width = ...」賦值和「Factory」是什麼？ –