ifelse语句只返回else值(与dplyr的if_else，loop相同)
ifelse语句只返回else值(与dplyr的if_else，loop相同)
提问于 2020-03-31 00:14:27
答案可能不是太牵强，我提前为此道歉。我正在做一个基本的网络抓取练习，基于我在网上找到的代码，但为了让我知道我在写什么，我有自己的想法。我设法添加了一年，数据和总统专栏，但我正在努力添加美国总统的党到我的df。结果总是一样的，所有的总统都被贴上了共和党的标签。
这是我的代码
library(rvest)
library(tidyr)
library(dplyr)
pres.library <- read_html(x = "http://stateoftheunion.onetwothree.net/texts/index.html")
links <- pres.library %>%
html_nodes("#text li a") %>%
html_attr("href")
text <- pres.library %>%
html_nodes("#text li a") %>%
html_text()
sotu <- data.frame (text = text, links = links, stringsAsFactors = F) %>%
separate(text, c("President", "Date", "Year"), ",")
sotu.modern <- sotu[-c(1:156),]
democrats <- c("Harry S. Truman", "John F. Kennedy", "Lyndon B. Johnson", "Jimmy Carter", "William J. Clinton", "Barack Obama")下面是ifelse语句。
sotu.modern$Party <- ifelse(sotu.modern$President %in% democrats, "Democrats", "Republican")我尝试使用dplyer的if_else函数&使用经典的if{} else {}循环/函数，但结果总是相同的。
提前感谢
回答 1
Stack Overflow用户
回答已采纳
发布于 2020-03-31 00:25:23
我运行了你的代码，并查看了unique(sotu.modern$President)，看起来每个名字都有一个前导空格，而奥巴马有一个尾随空格：
> unique(sotu$President)
[1] " George Washington" " John Adams" " Thomas Jefferson" " James Madison"
[5] " James Monroe" " John Quincy Adams" " Andrew Jackson" " Martin van Buren"
[9] " John Tyler" " James Polk" " Zachary Taylor" " Millard Fillmore"
[13] " Franklin Pierce" " James Buchanan" " Abraham Lincoln" " Andrew Johnson"
[17] " Ulysses S. Grant" " Rutherford B. Hayes" " Chester A. Arthur" " Grover Cleveland"
[21] " Benjamin Harrison" " William McKinley" " Theodore Roosevelt" " William H. Taft"
... 使用基本函数trimws()或stringr::str_trim将其删除。
sotu$President = trimws(sotu$President)
sotu.modern <- sotu[-c(1:156),]
sotu.modern$Party <- ifelse(sotu.modern$President %in% democrats, "Democrats", "Republican")
sotu.modern
sotu.modern
# President Date Year links Party
# 157 Harry S. Truman January 21 1946 19460121.html Democrats
# 158 Harry S. Truman January 6 1947 19470106.html Democrats
# 159 Harry S. Truman January 7 1948 19480107.html Democrats
# 160 Harry S. Truman January 5 1949 19490105.html Democrats
# 161 Harry S. Truman January 4 1950 19500104.html Democrats
# 162 Harry S. Truman January 8 1951 19510108.html Democrats
# 163 Harry S. Truman January 9 1952 19520109.html Democrats
# 164 Harry S. Truman January 7 1953 19530107.html Democrats
# 165 Dwight D. Eisenhower February 2 1953 19530202.html Republican
# 166 Dwight D. Eisenhower January 7 1954 19540107.html Republican
...页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/60934797
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