尽管变量中没有缺失值，但带有 for 循环的 if-else 条件会引发缺失值错误答案

【问题标题】：if-else condition with for loop throws up missing value error although no missing values in variables尽管变量中没有缺失值，但带有 for 循环的 if-else 条件会引发缺失值错误
【发布时间】：2020-05-12 11:00:27
【问题描述】：

我正在尝试编写一个循环来创建一个变量，以便稍后使用 group_by on 进行进一步计算，这表明特定类型（组变量）是否发生在两个日期（日期变量）之间。我要创建的因子称为leaderFactor。

代码抛出错误：“if (test1$party[i] == "PSOE" & test1$elecTypeDate[i] > as_date("1977-01-01") & 中的错误：需要 TRUE/FALSE 的缺失值”，但两个相关变量中没有缺失值。请帮忙！谢谢！

（旁注：这是一个具有两种以上事件类型的更复杂场景的示例，因此我将在下面的代码中的 if 和 else 之间使用几个 else if 语句。）

数据：

test1<- structure(list(party = c("PP", "PP", "PP", "PP", "PP", "PP", 
"PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", 
"PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", 
"PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", 
"PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", 
"PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", 
"PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", 
"PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", 
"PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", 
"PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", 
"PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", 
"PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", 
"PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", 
"PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", 
"PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", 
"PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", 
"PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", 
"PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", "PP", 
"PP", "PP", "PP", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", "PSOE", 
"PSOE", "PSOE", "PSOE", "PSOE"), elecTypeDate = structure(c(3346, 
3346, 3346, 3712, 4291, 4503, 4656, 4656, 4656, 4656, 4656, 4656, 
4656, 4656, 4656, 4656, 4656, 4656, 4656, 4868, 4868, 4868, 4868, 
4868, 4868, 4868, 4868, 4868, 4868, 4991, 4991, 4991, 5144, 5204, 
5783, 5995, 6148, 6209, 6360, 6360, 6360, 6360, 6360, 6360, 6360, 
6360, 6360, 6360, 6360, 6360, 6360, 6695, 6940, 7274, 7456, 7578, 
7790, 7790, 7790, 7790, 7790, 7790, 7790, 7790, 7790, 7790, 7790, 
7790, 7821, 8095, 8674, 8766, 8917, 9039, 9251, 9251, 9251, 9251, 
9251, 9251, 9251, 9251, 9251, 9282, 9282, 9282, 9435, 9556, 10135, 
10500, 10592, 10743, 10743, 10743, 10743, 10743, 10743, 10743, 
10743, 10743, 10743, 10743, 10835, 10865, 11017, 11443, 11596, 
12173, 12173, 12173, 12173, 12173, 12173, 12173, 12173, 12173, 
12204, 12204, 12296, 12326, 12357, 12418, 12478, 12874, 12935, 
13453, 13634, 13634, 13634, 13634, 13634, 13634, 13634, 13634, 
13634, 13634, 13665, 13695, 13939, 14245, 14245, 14304, 14304, 
14914, 15095, 15095, 15095, 15095, 15095, 15095, 15095, 15095, 
15095, 15095, 15095, 15095, 15126, 15400, 15400, 15614, 15614, 
15645, 16102, 16495, 16556, 16556, 16556, 16556, 16556, 16556, 
16556, 16556, 16556, 16556, 16556, 16556, 16587, 16679, 17045, 
17045, 17501, 17622, 17928, 17987, 18017, 18017, 18017, 18017, 
18017, 18017, 18017, 18017, 18017, 18017, 18017, 18017, 3346, 
3346, 3346, 3346, 3377, 3712, 3712, 4291, 4503, 4656, 4656, 4656, 
4656, 4656, 4656, 4656, 4656, 4656, 4656, 4656, 4656, 4656, 4868, 
4868, 4868, 4868, 4868, 4868, 4868, 4868, 4868, 4868, 4991, 4991, 
4991, 5144, 5204, 5783, 5995, 6148, 6209, 6360, 6360, 6360, 6360, 
6360, 6360, 6360, 6360, 6360, 6360, 6360, 6360, 6360, 6695, 6940, 
7274, 7456, 7578, 7790, 7790, 7790, 7790, 7790, 7790, 7790, 7790, 
7790, 7790, 7790, 7790, 7821, 8095, 8674, 8766, 8917, 9039, 9251, 
9251, 9251, 9251, 9251, 9251, 9251, 9251, 9251, 9251, 9282, 9282, 
9282, 9435, 9556, 10135, 10500, 10592, 10743, 10743, 10743, 10743, 
10743, 10743, 10743, 10743, 10743, 10743, 10743, 10743, 10835, 
10865, 11017, 11443, 11596, 12173, 12173, 12173, 12173, 12173, 
12173, 12173, 12173, 12173, 12173, 12204, 12204, 12296, 12326, 
12357, 12418, 12478, 12874, 12935, 13453, 13634, 13634, 13634, 
13634, 13634, 13634, 13634, 13634, 13634, 13634, 13634, 13665, 
13695, 13939, 14245, 14304, 14304, 14914, 15095, 15095, 15095, 
15095, 15095, 15095, 15095, 15095, 15095, 15095, 15095, 15095, 
15126, 15400, 15400, 15614, 15614, 15645, 16102, 16495, 16556, 
16556, 16556, 16556, 16556, 16556, 16556, 16556, 16556, 16556, 
16556, 16556, 16587, 16679, 17045, 17045, 17501, 17622, 17928, 
17987, 18017, 18017, 18017, 18017, 18017, 18017, 18017, 18017, 
18017, 18017, 18017, 18017), class = "Date")), row.names = c(NA, 
-398L), class = c("tbl_df", "tbl", "data.frame"))

代码：

test1$leaderFactor <- "none"
for(i in test1$leaderFactor){
  if(test1$party[i]=="PSOE" & 
     test1$elecTypeDate[i] > as_date("1977-01-01") & 
                               test1$elecTypeDate[i] < as_date("1997-06-30")){
    test1$leaderFactor[i] = "Gonzales"
   } else {
    test1$leaderFactor[i] = "Rest"}}
sum(is.na(test1$elecTypeDate))
sum(is.na(test1$party))

【问题讨论】：

顺便说一句，您无需将变量转换为因子即可使用group_by。
试试as.Date，对我有用。
df <- data.frame(group=rep(c(1,2),each=3), date=rep(c("2001-06-01", "2002-10-01", "2003-06-01"),2), stringsAsFactors = FALSE); df$futureFactor <- ifelse(df$group==1 & df$date > "2001-01-01" & df$date < "2002-12-31", "a", "b")
@jay.sf 使用 as.Date 而不是 as_date 会产生完全相同的错误。
@KonradRudolph 使用R 4.0.0，只加载了基础包，没有错误，抱歉。

标签： r for-loop if-statement

【解决方案1】：

首先，为什么要使用循环？不用循环也可以这样写：

df <- data.frame(
    group = rep(c(1, 2), each = 3),
    date = as_date(rep(c("2001-06-01", "2002-10-01", "2003-06-01"), 2))
)

df$futureFactor <- ifelse(
    df$group == 1
    & df$date > as_date("2001-01-01")
    & df$date < as_date("2002-12-31"),
    "a", "b"
)

生成的代码更短、更类似于 R 并且运行效率更高。

如果使用if 而不是ifelse，请始终使用&&（和||）而不是&（和|）：后者是矢量化的，但if 只接受单个值，如果提供多个值则失败，因此矢量化纯文本没有意义。

现在，为什么您的代码会失败？因为您正在尝试比较日期和因素，而 R 会给您一个有用的警告（这应该是一个错误）：

“>”的不兼容方法（“Ops.factor”、“>.Date”）

您需要通过使用as_date 定义df$date 来确保您的数据具有正确的类型，就像我在上面的代码中所做的那样。

【讨论】：

"旁注：这是一个具有两种以上事件类型的更复杂场景的示例，因此我将在下面的代码中的 if 和 else 之间使用几个 else if 语句。"跨度>
我意识到了因子-日期比较问题。您的回答是指我为说明问题而制作的一个示例，这并不是说其中一个变量不是日期。我现在只是直接从脚本中放入代码（尽管仍然不包括 else if in-betweeners）。
@Spaniel 对于两种以上的情况，您可以使用来自“dplyr”的case_when 而不是ifelse。

【解决方案2】：

解决方案是在 test1$leaderFactor 周围使用 seq_along()

【讨论】：