R 未从web刮取在数据框中输入值
我的主要目的是从网站中提取内容。我想在本地保存它。网站内容更新后,还应反映本地数据。R 未从web刮取在数据框中输入值,r,web-scraping,rvest,removing-whitespace,R,Web Scraping,Rvest,Removing Whitespace,我的主要目的是从网站中提取内容。我想在本地保存它。网站内容更新后,还应反映本地数据。 我可以从代码中使用的网页中读取数据,现在我想将结果保存到数据框中,以便导出结果。我希望x6的值应该输入到数据框df中,这样我可以将数据框结果导出到文本文件或excel文件中,或者您可以建议任何其他方法从代码中使用的网页中提取数据(网页抓取)。在这种情况下,我希望我的for循环不起作用,因此请任何人帮助我 library(rvest) library(dplyr) library(qdapRegex) # ins
我可以从代码中使用的网页中读取数据,现在我想将结果保存到数据框中,以便导出结果。我希望x6的值应该输入到数据框df中,这样我可以将数据框结果导出到文本文件或excel文件中,或者您可以建议任何其他方法从代码中使用的网页中提取数据(网页抓取)。在这种情况下,我希望我的for循环不起作用,因此请任何人帮助我
library(rvest)
library(dplyr)
library(qdapRegex) # install.packages("qdapRegex")
google <- read_html("https://bidplus.gem.gov.in/bidresultlists")
(x <- google %>%
html_nodes(".block") %>%
html_text())
class(x)
(x1 <- gsub(" ", "", x))
(x2 <- gsub(" ", "", x1))
(x3 <- gsub(" ", "", x2))
(x4 <- gsub(" ", "", x3))
(x5 <- gsub(" ", "", x4))
(x6 <- gsub("\n", "", x5))
class(x6)
length(x6[i])
typeof(x6)
for (i in x6) {
BIDNO <- rm_between(x6[i], "BID NO:", "Status", extract = TRUE)
Status <- rm_between(x6[i], "Status:", "Quantity Required", extract = TRUE)
Quantity_Required <- rm_between(x6[i], "Quantity Required:", "Department Name And Address", extract = TRUE)
Department_Name_And_Address <- rm_between(x6[i], "Department Name And Address:", "Start Date", extract = TRUE)
Start_Date <- rm_between(x6[i], "Start Date:", "End Date", extract = TRUE)
# End_Date <- rm_between(x6[i], "End Date: ", "Technical Evaluation", extract=TRUE)
df <- data.frame("BID_NO", "Status", "Quantity_Required", "Department_Name_Address", "Start_Date")
}
df
View(df)
库(rvest)
图书馆(dplyr)
库(qdapRegex)#安装程序包(“qdapRegex”)
谷歌%
html_text())
类别(x)
(x1问题似乎在于您创建的是一组带引号的字符串,其中包含“BID_NO”等。如果您试图将值保存到数据帧中,则需要将保存值的变量名保存到数据帧中
df问题似乎是您创建的是一组带引号的字符串。如果您试图将值保存到数据框中,则需要将保存值的变量名保存到数据框中
df使用XPath以所需元素为目标很可能是一条挫折和错误较少的路径:
library(rvest)
library(dplyr)
pg <- read_html("https://bidplus.gem.gov.in/bidresultlists")
针对具有bid#和状态的块标题:
block_header <- html_nodes(blocks, "div.block_header")
退出状态:
html_nodes(block_header, xpath=".//p/b[contains(., 'Status')]/following-sibling::span") %>%
html_text(trim=TRUE) -> status
目标和退出开始和结束日期:
html_nodes(blocks, xpath=".//strong[contains(., 'Start Date')]/following-sibling::span") %>%
html_text(trim=TRUE) -> start_date
html_nodes(blocks, xpath=".//strong[contains(., 'End Date')]/following-sibling::span") %>%
html_text(trim=TRUE) -> end_date
制作一个数据帧:
data.frame(
bid_no,
status,
start_date,
end_date,
items,
quantity,
department_name_and_address,
stringsAsFactors=FALSE
) -> xdf
str(xdf)
## 'data.frame': 10 obs. of 8 variables:
## $ bid_no : chr "GEM/2018/B/93066" "GEM/2018/B/93082" "GEM/2018/B/93105" "GEM/2018/B/93999" ...
## $ status : chr "Not Evaluated" "Not Evaluated" "Not Evaluated" "Not Evaluated" ...
## $ start_date : chr "25-09-2018 03:53:pm" "27-09-2018 09:16:am" "25-09-2018 05:08:pm" "26-09-2018 05:21:pm" ...
## $ end_date : chr "18-10-2018 03:00:pm" "18-10-2018 03:00:pm" "18-10-2018 03:00:pm" "18-10-2018 03:00:pm" ...
## $ items : chr "automotive chassis fitted with engine" "automotive chassis fitted with engine" "automotive chassis fitted with engine" "Storage System" ...
## $ quantity : num 1 1 1 2 90 1 981 6 4 376
## $ department_name_and_address: chr "Department Name And Address:||Ministry Of Steel Na Kirandul Complex N/a" "Department Name And Address:||Ministry Of Steel Na Kirandul Complex N/a" "Department Name And Address:||Ministry Of Steel Na Kirandul Complex N/a" "Department Name And Address:||Maharashtra Energy Department Maharashtra Bhusawal Tps N/a" ...
## $ is_ra : logi FALSE FALSE FALSE FALSE FALSE FALSE ...
有些投标是“RA
”的,因此我们还可以创建一个专栏,让我们知道哪些是:
xdf$is_ra <- grepl("/RA/", bid_no)
我将让您将日期转换为POSIXct
元素
不带解释的连续代码为
此外,这不是Java。for
循环很少是R中问题的解决方案。而且,您应该仔细阅读正则表达式,因为计算替换空间也是一条充满危险和挫折的路径。使用XPath针对所需元素可能是一条挫折和错误较少的路径:
library(rvest)
library(dplyr)
pg <- read_html("https://bidplus.gem.gov.in/bidresultlists")
针对具有bid#和状态的块标题:
block_header <- html_nodes(blocks, "div.block_header")
退出状态:
html_nodes(block_header, xpath=".//p/b[contains(., 'Status')]/following-sibling::span") %>%
html_text(trim=TRUE) -> status
目标和退出开始和结束日期:
html_nodes(blocks, xpath=".//strong[contains(., 'Start Date')]/following-sibling::span") %>%
html_text(trim=TRUE) -> start_date
html_nodes(blocks, xpath=".//strong[contains(., 'End Date')]/following-sibling::span") %>%
html_text(trim=TRUE) -> end_date
制作一个数据帧:
data.frame(
bid_no,
status,
start_date,
end_date,
items,
quantity,
department_name_and_address,
stringsAsFactors=FALSE
) -> xdf
str(xdf)
## 'data.frame': 10 obs. of 8 variables:
## $ bid_no : chr "GEM/2018/B/93066" "GEM/2018/B/93082" "GEM/2018/B/93105" "GEM/2018/B/93999" ...
## $ status : chr "Not Evaluated" "Not Evaluated" "Not Evaluated" "Not Evaluated" ...
## $ start_date : chr "25-09-2018 03:53:pm" "27-09-2018 09:16:am" "25-09-2018 05:08:pm" "26-09-2018 05:21:pm" ...
## $ end_date : chr "18-10-2018 03:00:pm" "18-10-2018 03:00:pm" "18-10-2018 03:00:pm" "18-10-2018 03:00:pm" ...
## $ items : chr "automotive chassis fitted with engine" "automotive chassis fitted with engine" "automotive chassis fitted with engine" "Storage System" ...
## $ quantity : num 1 1 1 2 90 1 981 6 4 376
## $ department_name_and_address: chr "Department Name And Address:||Ministry Of Steel Na Kirandul Complex N/a" "Department Name And Address:||Ministry Of Steel Na Kirandul Complex N/a" "Department Name And Address:||Ministry Of Steel Na Kirandul Complex N/a" "Department Name And Address:||Maharashtra Energy Department Maharashtra Bhusawal Tps N/a" ...
## $ is_ra : logi FALSE FALSE FALSE FALSE FALSE FALSE ...
有些投标是“RA
”的,因此我们还可以创建一个专栏,让我们知道哪些是:
xdf$is_ra <- grepl("/RA/", bid_no)
我将让您将日期转换为POSIXct
元素
不带解释的连续代码为
此外,这不是Java。for
循环很少是R中问题的解决方案。而且,你应该仔细阅读正则表达式,因为计算替换空间也是一条充满危险和挫折的道路。如果我想从上述网站中的所有网页中提取数据,那么我该怎么做……如果我想提取数据从所有网页在上述网站上,那么我应该怎么做。。。