我正在尝试使用 R 从类似于以下http://www.fec.gov/pubrec/fe1996/hraz.htm的表中读取数据,但无法取得进展。我意识到要这样做,我需要使用XML和RCurl,但是尽管网上有很多关于类似问题的其他例子,我还是无法解决这个问题。
第一个问题是该表在查看时只是一个表,但没有这样编码。将它作为一个xml文档处理我可以访问表中的“数据”,但因为有几个表我想得到,我不相信这是最优雅的解决方案。
将其作为html文档处理可能会更好,但我对xpathApply相对不熟悉,并且不知道如何获取表中的实际“数据”,因为它没有被任何东西括起来(即i- / i或B- / b)。
我过去使用xml文件取得了一些成功,但这是我第一次尝试使用html文件做类似的事情。特别是这些文件似乎比我见过的其他例子的结构更少。
非常感谢任何帮助。
答案 0 :(得分:1)
假设您可以将html
输出读入文本文件(相当于从Web浏览器复制+粘贴),
这应该会让你在那里得到很好的一块:
# x is the output from the website
library(stringr)
library(data.table)
# First, remove commas from numbers (easiest to do at beginning)
x <- gsub(",([0-9])", "\\1", x)
# split the data by District
districts <- strsplit(x, "DISTRICT *")[[1]]
# separate out the header info
headerInfo <- districts[[1]]
districts <- tail(districts, -1)
# grab the straggling district number, use it as a name and remove it
# end of first line
eofl <- str_locate(districts, "\n")[,2]
# trim white space and assign as name
names(districts) <- str_trim(substr(districts, 1, eofl))
# remove first line
districts <- substr(districts, eofl+1, nchar(districts))
# replace the ending '-------' and trime white space
districts <- str_trim(str_replace_all(districts, "---*", ""))
# Adjust delimeter (this is the tricky part)
## more than two spaces are a spearator
districts <- str_replace_all(districts, " +", "\t")
## lines that are total tallies are missing two columns.
## thus, need to add two extra delims. After the first and third columns
# this function will
padDelims <- function(section, splton) {
# split into lines
section <- strsplit(section, splton)[[1]]
# identify lines starting with totals
LinesToFix <- str_detect(section, "^Total")
# pad appropriate columns
section[LinesToFix] <- sub("(.+)\t(.+)\t(.*)?", "\\1\t\t\\2\t\t\\3", section[LinesToFix])
# any rows missing delims, pad at end
counts <- str_count(section, "\t")
toadd <- max(counts) - counts
section[ ] <- mapply(function(s, p) if (p==0) return (s) else paste0(s, paste0(rep("\t", p), collapse="")), section, toadd)
# paste it back together and return
paste(section, collapse=splton)
}
districts <- lapply(districts, padDelims, splton="\n")
# reading the table and simultaneously addding the district column
districtTables <-
lapply(names(districts), function(d)
data.table(read.table(text=districts[[d]], sep="\t"), district=d) )
# ... or without adding district number:
## lapply(districts, function(d) data.table(read.table(text=d, sep="\t")))
# flatten it
votes <- do.call(rbind, districtTables)
setnames(votes, c("Candidate", "Party", "PrimVotes.Abs", "PrimVotes.Perc", "GeneralVotes.Abs", "GeneralVotes.Perc", "District") )
样本表:
votes
Candidate Party PrimVotes.Abs PrimVotes.Perc GeneralVotes.Abs GeneralVotes.Perc District
1: Salmon, Matt R 33672 100.00 135634.00 60.18 1
2: Total Party Votes: 33672 NA NA NA 1
3: NA NA NA NA 1
4: Cox, John W(D)/D 1942 100.00 89738.00 39.82 1
5: Total Party Votes: 1942 NA NA NA 1
6: NA NA NA NA 1
7: Total District Votes: 35614 NA 225372.00 NA 1
8: Pastor, Ed D 29969 100.00 81982.00 65.01 2
9: Total Party Votes: 29969 NA NA NA 2
10: NA NA NA NA 2
...
51: Hayworth, J.D. R 32554 100.00 121431.00 47.57 6
52: Total Party Votes: 32554 NA NA NA 6
53: NA NA NA NA 6
54: Owens, Steve D 35137 100.00 118957.00 46.60 6
55: Total Party Votes: 35137 NA NA NA 6
56: NA NA NA NA 6
57: Anderson, Robert LBT 148 100.00 14899.00 5.84 6
58: NA NA NA NA 6
59: Total District Votes: 67839 NA 255287.00 NA 6
60: NA NA NA NA 6
61: Total State Votes: 368185 NA 1356446.00 NA 6
Candidate Party PrimVotes.Abs PrimVotes.Perc GeneralVotes.Abs GeneralVotes.Perc District