在 R 中进行子集化时出错 - 空数据框

Question

我正在使用函数 subset 对数据框进行子集化，但没有成功：

这是我的数据框

> dput(df)
structure(list(Station = c("S09489500", "S09498500", "S09510200", 
"S09494000", "S09497500", "S09492400", "S09504500", "S09503700"
), location = c("back", "back", "ahead", "ahead", "back", "ahead", 
"ahead", "ahead"), length_years = c(36L, 75L, 33L, 34L, 75L, 
35L, 49L, 34L), begin = c(1985, 1946, 1962, 1959, 1946, 1958, 
1949, 1964), end = c(2020, 2020, 1994, 1992, 2020, 1992, 1997, 
1997), Utest_Q7min = c(26.3618474823095, 119.756524166147, 12.749016687539, 
20.3410125011518, 92.9397377831962, 19.8329511433346, 18.5949830661337, 
34.4767872640756), Significance_Qtest_Q7min = c("No Independent", 
"No Independent", "No Independent", "No Independent", "No Independent", 
"No Independent", "No Independent", "No Independent"), PT_U = c(124, 
567, 98, 181, 646, 158, 94, 238), ChangePoint_Q7min = c(26L, 
19L, 9L, 17L, 29L, 23L, 30L, 16L), p_Q7min = c(0.292065629512458, 
0.0219501976437697, 0.42182506012988, 0.0155276557662876, 0.00571923921900464, 
0.0669830682326448, 1.28599300599023, 0.000449734648357696), 
    Significance_ChangePoint_Q7min = c("No significant", "Significant", 
    "No significant", "Significant", "Significant", "No significant", 
    "No significant", "Significant"), Man_Kendall = c("category 2", 
    "category 1", "category 1", "category 3", "category 1", "category 3", 
    "category 1", "category 3")), class = "data.frame", row.names = c(NA, 
-8L))

我正在使用以下代码进行子集化：

  df2 <- subset(df,df$Significance_ChangePoint_Q7min=="Significant" && df$Significance_Qtest_Q7min == "No Independent")

但结果我得到了一个空数据框。

有人知道为什么子集在这种情况下不起作用吗？

Answer 1

试试这个：

df2 <- subset(df, df$Significance_ChangePoint_Q7min == "Significant" & 
                df$Significance_Qtest_Q7min == "No Independent")

单人&

Answer 2

使用filter

library(dplyr)
df %>% 
     filter(Significance_ChangePoint_Q7min == "Significant" &
              Significance_Qtest_Q7min == "No Independent")

Answer 3

这不起作用的原因是双重 &&。在这种情况下，您需要执行一个 &。

你想做的是比较多个值并得到一个 vector 或 TRUE 或 FALSE 值两个变量是 TRUE 或 FALSE。单个 & 执行此操作。

双 && 只会检查变量中的第一个值（即数据框的第一行）和 returns 单个 TRUE 或 FALSE值而不是向量。

Answer 4

require(dplyr)
df2 <- df %>% filter(Significance_ChangePoint_Q7min == "Significant" & Significance_Qtest_Q7min == "No Independent")



> df2
    Station location length_years begin  end Utest_Q7min Significance_Qtest_Q7min PT_U ChangePoint_Q7min      p_Q7min Significance_ChangePoint_Q7min Man_Kendall
1 S09498500     back           75  1946 2020   119.75652           No Independent  567                19 0.0219501976                    Significant  category 1
2 S09494000    ahead           34  1959 1992    20.34101           No Independent  181                17 0.0155276558                    Significant  category 3
3 S09497500     back           75  1946 2020    92.93974           No Independent  646                29 0.0057192392                    Significant  category 1
4 S09503700    ahead           34  1964 1997    34.47679           No Independent  238                16 0.0004497346                    Significant  category 3

在 R 中进行子集化时出错 - 空数据框

Error when subsetting in R - empty data frame

testing

variables

statistics

r

subset