Question

我有数据帧df.1和df.2（从实际数据帧中提取）

df.1<-structure(list(a = c(47.22, 88.89, 71.88, NA, 75, 100, 72.22, 
94.44, 52.78, 86.11, 66.67), b = c(46.88, 80.56, 80.56, NA, 31.25, 
100, 52.78, 100, 31.25, 91.67, 58.33)), .Names = c("a", "b"), row.names = 2330:2340, class = "data.frame")

df.2<-structure(list(a = c(75, 47.22, 86.11, 93.75, 86.11, 77.78, 91.67, 
100, 38.89, 97.22, 100), b = c(71.88, 72.22, 83.33, NA, 50, 69.44, 
100, 100, 53.13, 91.67, 88.89)), .Names = c("a", "b"), row.names = 2330:2340, class =   "data.frame")

尝试将pmin或pmax函数应用于这些数据帧会导致错误：

 pmax (df.1, df.2)
 Error in `[.data.frame`(each, nas[, 1L]) : undefined columns selected

我完全不知道它为什么会发生，pmax和pmin在我的实际数据帧的其他部分工作得很好，它们看起来非常类似于这些数据。我非常感谢你的帮助。

以下是会话信息：

(sessionInfo())
 R version 2.14.2 (2012-02-29)
 Platform: i386-pc-mingw32/i386 (32-bit)

 locale:
 [1] LC_COLLATE=English_United States.1252  LC_CTYPE=English_United States.1252        LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C                           LC_TIME=English_United States.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] stringr_0.6.2    plyr_1.8         Revobase_6.1.0   RevoMods_6.1.0     RevoScaleR_3.1-0 lattice_0.20-0   rpart_3.1-51    

loaded via a namespace (and not attached):
[1] codetools_0.2-8 foreach_1.4.0   grid_2.14.2     iterators_1.0.6 tools_2.14.2

Answer 1

在运行matrix或pmax之前，尝试将这两个数据框转换为pmin：

pmax(as.matrix(df.1), as.matrix(df.2))

#         a      b
# 2330  75.00  71.88
# 2331  88.89  80.56
# 2332  86.11  83.33
# 2333     NA     NA
# 2334  86.11  50.00
# 2335 100.00 100.00
# 2336  91.67 100.00
# 2337 100.00 100.00
# 2338  52.78  53.13
# 2339  97.22  91.67
# 2340 100.00  88.89

来源：?pmax“pmax和pmin将一个或多个向量（或矩阵）作为参数......”

Answer 2

尚不确定（尚未）如何解决此问题，但似乎是围绕在比较的第一个数据集中出现的NAs。您可以通过一次更改一个NA并尝试重新运行代码来确认这一点。

解决方法是创建一个首先考虑的虚拟data.frame

df.0<-structure(list(a =rep(0,11),b=rep(0,11)), .Names = c("a", "b"), row.names =  2330:2340, class = "data.frame")
df.1<-structure(list(a = c(47.22, 88.89, 71.88, NA, 75, 100, 72.22, 
                       94.44, 52.78, 86.11, 66.67), b = c(46.88, 80.56, 80.56, NA, 31.25, 
                       100, 52.78, 100, 31.25, 91.67, 58.33)), .Names = c("a", "b"), row.names = 2330:2340, class = "data.frame")

df.2<-structure(list(a = c(75, 47.22, 86.11, 93.75, 86.11, 77.78, 91.67, 
                           100, 38.89, 97.22, 100), b = c(71.88, 72.22, 83.33, NA, 50, 69.44, 
                            100, 100, 53.13, 91.67, 88.89)), .Names = c("a", "b"), row.names = 2330:2340, class =   "data.frame")

pmax(df.0,df.1, df.2)

pmin和pmax出错“`[.data.frame`（每个，nas [，1L]）出错：选择了未定义的列”

2 个答案: