我正在尝试开发一个简单的应用程序，从Kijiji网站获取本地分类广告。我已经制作了一个类似的应用程序，几乎完全相同的脚本，但我没有得到下面描述的错误，所以我不知道这个脚本出了什么问题。我尝试了所有我能想到的东西，但无法让它发挥作用。
df中server.R数据框的结构如下:(请注意，我已截断值以使其更具可读性）
'data.frame': 38 obs. of 7 variables:
$ Title : chr "Baby-boy 3-6 month" ...
$ Price : num 0 6.92 8 10 10 15 15 15 20 20 ...
$ Short.Description: chr "Give for free ..."
$ Address : chr "Calgary, AB T2Z 0V6" "341 ..."
$ Date : Date, format: "2014-12-05" "2014-10-28" "2014-12-05" ...
$ Full.Description : chr "Give for free some ..."
$ Link : chr "http://www.kijiji...."
可以按如下方式复制:(一个包含5条记录的样本用于演示目的）
df <- data.frame(
Title= c("Baby-boy 3-6 month","Giggle Life Optimize Cloth Diapers & 4 layer mixed insert", "Beluga Baby","Baby sled", "Avent Sterilizer & Various Medela Items"),
Price= c(0.00, 6.92, 8.00, 10.00, 10.00),
Short.Description=c("Give for free some staff for boy 3-6 month. Live in New Brighton, SE", "If you have any questions or are looking to order please don't hesitate to call our local line 587-774-2404, toll free line 1-877-883-3069 or visit our website…","Calgary! Fall in love with your all natural and freshly handmade products for mama and baby. www.belugaskincare.com Like us on Facebook.com/belugaskincare FREE shipping in Canada with a $25 cart!…", "Yellow plastic baby sled Safety seat belt Tow rope Dimensions: 23\" long x 14 1/2\" wide x 12\" high $10 Located in Willow Park off Southland Dr. and Fairmount Dr. SE CALL: 403 460 - 0978 (will not…", "Avent microwave sterilizer in good condition 1 Avent bottle 2 Medela bottles 1/2 box of unused Medela pump and save bags 1bag of replaceable Medela pump parts From clean, smoke free home. Take all…"),
Address=c("Calgary, AB T2Z 0V6","341 Westvale Drive, Waterloo, ON N2T 2M2","Canada", "Calgary, AB T2J 1H6, Canada","Calgary, AB T2W, Canada"),
Date=c(as.Date(c( "2014-12-05", "2014-10-28", "2014-12-05", "2014-12-05", "2014-12-05"))),
Full.Description=c("Give for free some staff for boy 3-6 month. Live in New Brighton, SE", "If you have any questions or are looking to order please don't hesitate to call our local line 587-774-2404, toll free line 1-877-883-3069 or visit our website http://www.gigglelife.com/catalog/?Calgary. \rEnter the promo code \"KIJCALGARY\" in the comment box when ordering to receive a free gift with your order.\rThe new Giggle Life Optimize Cloth Diaper is very affordable, effective, and comfortable. It is simply the best value on market. These reusable diapers are one size fits all (7-36lbs). \rThey are $6.92 each when you purchase 12. Please note there is a $1 surcharge for pattern designs. \rManufacturer’s Warranty \rSupport for as long as you use the diapers! \r****FREE SHIPPING ACROSS CANADA!!**** \rAll diapers are new and individually packaged - never worn OR washed. They are high quality, one-size-fits-all, pocket cloth diapers. \rAll orders are shipped via Canada Post within 24 hours of placing your order. We send all packages Expedited with insurance and a tracking number, which is provided immediately upon shipping out. \rLooking for other package sizes? We have packages of 10, 24, 38 and 100 also..", "Calgary! Fall in love with your all natural and freshly handmade products for mama and baby. www.belugaskincare.com Like us on Facebook.com/belugaskincare FREE shipping in Canada with a $25 cart! \"making life simpler and greener so you can better do the things you are most passionate about\" - Beluga Skin CareThis ad was posted with the Kijiji mobile app.This ad was posted WITH the Kijiji mobile app.", "Yellow plastic baby sledSafety seat beltTow ropeDimensions: 23\" long x 14 1/2\" wide x 12\" high$10Located in Willow Park off Southland Dr. and Fairmount Dr. SECALL: 403 460 - 0978 (will not respond to texts at this land line number) TEXT OR CALL: 403 463 - 1038PLEASE SEE MY OTHER ADSThis ad was posted with the Kijiji mobile app.This ad was posted WITH the Kijiji mobile app.","Avent microwave sterilizer in good condition1 Avent bottle2 Medela bottles1/2 box of unused Medela pump and save bags1bag of replaceable Medela pump partsFrom clean, smoke free home. Take all for 10$This ad was posted with the Kijiji mobile app.This ad was posted WITH the Kijiji mobile app."),
Link= c("http://www.kijiji.ca/v-baby-clothes-3-6-months/calgary/baby-boy-3-6-month/1037502424","http://www.kijiji.ca/v-baby-bathing-changing-diapers/calgary/giggle-life-optimize-cloth-diapers-4-layer-mixed-insert/1008481541?src=topAdSearch", "http://www.kijiji.ca/v-baby-bathing-changing-diapers/calgary/beluga-baby/1037483143" , "http://www.kijiji.ca/v-baby-toy/calgary/baby-sled/1037493662", "http://www.kijiji.ca/v-baby-feeding-high-chair/calgary/avent-sterilizer-various-medela-items/1037481182" )
)
这里是server.R。请注意，我已经注释掉了源代码，以避免提供源代码和延迟计算。请使用上面给出的df数据框重现结果：
#Install required packages
ListofPackages= c('shiny','ggplot2','scales')
NewPackages= ListofPackages[!(ListofPackages %in% installed.packages()[,'Package'])]
if(length(NewPackages)>0) install.packages(NewPackages)
#Load required packages
lapply(ListofPackages,require,character.only=TRUE)
#Load source code
#source('C:/Users/Bahae.Omid/Google Drive/My R Case Studies/Shiny Apps/Kijiji App/adscraper.R',local=TRUE)
shinyServer(function(input,output){
#Create a reactive function to deal with inputs of the user
search <- reactive({
if(length(input$t)>0) {ind <- grep(input$t,df[,'Title'],ignore.case = T); df <- df[ind,] }
if(length(input$d)>0) {ind <- grep(input$d,df[,'Full.Description'],ignore.case = T); df <- df[ind,]}
if(length(input$a)>0) {ind <- grep(input$a,df[,'Address'],ignore.case = T); df <- df[ind,]}
if(input$p >=0) {ind <- df[,'Price']<=input$p ; df <- df[ind,]}
})
#Send the searchresult table to ui.R
output$searchresult <- renderDataTable({
input$action1 #triggered only when button is pressed
if(input$action1==0) return()
else{isolate({
transformed <- transform(search(), URL = paste('<a href = ', shQuote(Link), '>', 'Click</a>'))
transformed[-7] #Remove the old Link column
})
}
}, option=list(autoWidth=FALSE,pageLength=100,
columnDefs = list(list(targets =c(2,5,7) -1, searchable = FALSE),list(sWidth="75px",aTargets = list(4,5)))))
#Allow user to download the data via downloadhandler
output$down <- downloadHandler(
filename='filtered.csv',
content=function(file){write.csv(search(),file,row.names=FALSE)}
)
})
这里是ui.R。请注意，我已经注释掉了图像标记，以避免在运行代码时出错：
shinyUI(fluidPage(
#Display datatable filters on top
tags$head(tags$style("tfoot {display: table-header-group;}")),
#Add a title
#img(src="kijiji.gif", height = 100, width = 100),
#img(src="plus.png", height = 20, width = 20),
#img(src="plus.png", height = 20, width = 20),
#Use the Sidebar layout
sidebarLayout(
sidebarPanel(
#Add fields to search by and download button to allow exporting search results to csv.
h5('Note: Running the app takes a little while to run at startup.'),
helpText('Ad Title:'),
textInput('t',''),
helpText('Description:'),
textInput('d',''),
helpText('Address:'),
textInput('a',''),
sliderInput('p','Show Prices up to:',min = 0,max = 10000,step = 50,value = 10000),
actionButton('action1','Search!'),
br(),
br(),
helpText('Click below to download the results of your search:'),
downloadButton('down','Download')
),
mainPanel(
dataTableOutput('searchresult')
)
)
))
当我运行应用程序时，所有过滤器似乎工作正常但是当过滤器没有返回数据框中的记录（即0行数据帧）时，我收到以下错误：
Error in data.frame(structure(list(Title = character(0), Price = numeric(0), :
arguments imply differing number of rows: 0, 1
我使用renderTable而不是renderDataTable测试了相同的脚本，并且它运行得非常好。但我希望以DataTable格式输出，特别是我能够在另一个相同的应用程序中使用它。
如果您需要更多说明，请与我们联系。
答案 0 :(得分：1)
当search()返回零行数data.frame
paste('<a href = ', shQuote(search()$url), '>', 'Click</a>')
返回
"<a href = \"\" > Click</a>"
然后，您尝试将此新行与一行绑定到没有行的data.frame。因此错误信息。
您可以使用
之类的东西修复它 transformed <- transform(search()
, Link = if(length(url) > 0){
paste('<a href = ', shQuote(url), '>', 'Click</a>')
}else{
character(0)
}
)
答案 1 :(得分：0)
基本上错误说：没有什么可以显示。所以使用browser（）并检查控制台中的当前输出是什么