我试图计算行和行之间的时差,该行具有符合某些条件的列。
阅读一些数据:
my_data <- data.frame(criteria = c("some text", "some more text", " ", " ", "more text", " "),
timestamp = as.POSIXct(c("2015-07-30 15:53:15", "2015-07-30 15:53:47", "2015-07-30 15:54:48", "2015-07-30 15:55:48", "2015-07-30 15:56:48", "2015-07-30 15:57:49")))
criteria timestamp
1 some text 2015-07-30 15:53:15
2 some more text 2015-07-30 15:53:47
3 2015-07-30 15:54:48
4 2015-07-30 15:55:48
5 more text 2015-07-30 15:56:48
6 2015-07-30 15:57:49
我想获得条件列中不是空白的每一行和最后一行之间的时差(以分钟为单位)。因此,我想:
criteria timestamp time_diff
1 some text 2015-07-30 15:53:15 0
2 some more text 2015-07-30 15:53:47 0
3 2015-07-30 15:54:48 1
4 2015-07-30 15:55:48 2
5 more text 2015-07-30 15:56:48 0
6 2015-07-30 15:57:49 1
到目前为止,我已经构建了代码来识别&#34; 0&#34;&#34;应该 - 我只需要代码来填补时差。这是我的代码:
my_data$time_diff <- ifelse (my_data$criteria != "", # Here's our statement
my_data$time_diff <- "0", # Here's what happens if statement is TRUE
my_data$time_diff <- NEED CODE HERE # if statement FALSE
)
我觉得这项工作可能更好地通过ifelse
陈述来表达,但我对R来说相对较新。
我在这里找到了个人试图在相邻行之间获得时间差异的地方(例如here和here),但还没有找到有人试图处理有这种情况。
我发现的最接近的问题是this one,但是这个数据与我个人想要处理它们的方式不同(至少从我的观点来看)。
编辑:大写标题。
答案 0 :(得分:2)
用alexis_laz的高手表达完成答案:
my_data <- data.frame(criteria = c("some text", "some more text", " ", " ", "more text", " "),
timestamp = as.POSIXct(c("2015-07-30 15:53:15", "2015-07-30 15:53:47", "2015-07-30 15:54:48", "2015-07-30 15:55:48", "2015-07-30 15:56:48", "2015-07-30 15:57:49")))
my_data$time_diff <-
my_data$timestamp -
my_data[cummax((my_data$criteria != " ") * seq_len(nrow(my_data))), 'timestamp']
my_data
criteria timestamp time_diff
1 some text 2015-07-30 15:53:15 0 secs
2 some more text 2015-07-30 15:53:47 0 secs
3 2015-07-30 15:54:48 61 secs
4 2015-07-30 15:55:48 121 secs
5 more text 2015-07-30 15:56:48 0 secs
6 2015-07-30 15:57:49 61 secs