Question

在R中我试图添加一些只有几小时的额外列。

我有一个名为Time的列：

我想要一个额外的专栏：

时间：

列时间来自“因子”类型。当我尝试这个时：

library(lubridate)
data$hour <- hour(hm(c(data$Time)))

我收到警告：

Warning message:
In .parse_hms(..., order = "HM", quiet = quiet):
  some strings failed to parse

我不明白为什么会出错。有人能帮我吗？

Answer 1

从c()移除hour(hm(c(data$Time)))来电。

通过将data$Time与c()包装在一起，就会迫使因子丢弃其属性。这只会导致其整数值，并且在传递给hm()时无法解析。

x <- factor(c("09:30", "09:45", "10:00", "10:40"))

## everything is fine
x    
# [1] 09:30 09:45 10:00 10:40
# Levels: 09:30 09:45 10:00 10:40

## wrapped with c() --> attributes dropped
c(x) 
# [1] 1 2 3 4

## wrapped with c() --> attributes dropped --> parsing fails
lubridate::hm(c(x))  
# [1] NA NA NA NA
# Warning message:
# In .parse_hms(..., order = "HM", quiet = quiet) :
#   Some strings failed to parse

## remove c() --> everything is fine
lubridate::hm(x)
# [1] "9H 30M 0S"  "9H 45M 0S"  "10H 0M 0S"  "10H 40M 0S"

所以只需将代码更改为

即可

data$Time <- hour(hm(data$Time))

尝试从时间中提取小时时发出警告

1 个答案: