r - 尝试在包含日期的数据帧上使用 melt() 时出现错误

Question

我想融合 dataframe 以便在一列中我有日期，然后我有用户名作为变量，最后是值。

我收到此错误:

Error in as.Date.numeric(value) : 'origin' must be supplied

虽然我理解错误，但我不确定如何解决它。

数据的一个小样本是:

structure(list(created_at = structure(c(14007, 14008, 14009, 
14010, 14011, 14012), class = "Date"), benjamin = c(16, 0, 0, 
0, 0, 0), byron = c(0, 0, 0, 0, 0, 0), cameronc = c(0, 0, 0, 
0, 0, 0), daniel = c(0, 0, 0, 0, 0, 0), djdiaz = c(0, 0, 0, 0, 
0, 0), gene = c(16, 77, 64, 38, 72, 36), joel = c(0, 0, 0, 0, 
0, 2), kerem = c(0, 0, 0, 0, 0, 0), sophia = c(0, 0, 0, 0, 0, 
0), SuperMoonMan = c(0, 0, 0, 0, 0, 0)), .Names = c("created_at", 
"benjamin", "byron", "cameronc", "daniel", "djdiaz", "gene", 
"joel", "kerem", "sophia", "SuperMoonMan"), row.names = c(NA, 
6L), class = c("cast_df", "data.frame"))

感谢您的帮助。

Answer 1

尝试将 created_at 变量转换为字符向量。 melt 似乎也不喜欢 cast_df 类，但我成功地将类重置为 data.frame。像这样:

df <- as.data.frame(df)
df$created_at <- as.character(df$created_at)
library(reshape)
melt(df)