我有一个电晕数据，日期列是一个因子变量。我想只取5月的数据，我知道我可以通过计算行数来取，但是我想用日期列来取。我知道我可以通过计算行数来计算，但是我想用日期列来计算。
我是这样尝试的。
spndata <- data[data$iso_code == "ESP" & as.numeric(2020-05-01) < data$date < as.numeric(2020-06-01),]
日期是按年-月-日的顺序排列的，谢谢。
class = "factor"), date = structure(1:6, .Label = c("2019-12-31",
"2020-01-01", "2020-01-02", "2020-01-03", "2020-01-04", "2020-01-05",
"2020-01-06", "2020-01-07", "2020-01-08", "2020-01-09", "2020-01-10",
"2020-01-11", "2020-01-12", "2020-01-13", "2020-01-14", "2020-01-15",
"2020-01-16", "2020-01-17", "2020-01-18", "2020-01-19", "2020-01-20",
"2020-01-21", "2020-01-22", "2020-01-23", "2020-01-24", "2020-01-25",
"2020-01-26", "2020-01-27", "2020-01-28", "2020-01-29", "2020-01-30",
"2020-01-31", "2020-02-01", "2020-02-02", "2020-02-03", "2020-02-04",
"2020-02-05", "2020-02-06", "2020-02-07", "2020-02-08", "2020-02-09",
"2020-02-10", "2020-02-11", "2020-02-12", "2020-02-13", "2020-02-14",
"2020-02-15", "2020-02-16", "2020-02-17", "2020-02-18", "2020-02-19",
"2020-02-20", "2020-02-21", "2020-02-22", "2020-02-23", "2020-02-24",
"2020-02-25", "2020-02-26", "2020-02-27", "2020-02-28", "2020-02-29",
"2020-03-01", "2020-03-02", "2020-03-03", "2020-03-04", "2020-03-05",
"2020-03-06", "2020-03-07", "2020-03-08", "2020-03-09", "2020-03-10",
"2020-03-11", "2020-03-12", "2020-03-13", "2020-03-14", "2020-03-15",
"2020-03-16", "2020-03-17", "2020-03-18", "2020-03-19", "2020-03-20",
"2020-03-21", "2020-03-22", "2020-03-23", "2020-03-24", "2020-03-25",
"2020-03-26", "2020-03-27", "2020-03-28", "2020-03-29", "2020-03-30",
"2020-03-31", "2020-04-01", "2020-04-02", "2020-04-03", "2020-04-04",
"2020-04-05", "2020-04-06", "2020-04-07", "2020-04-08", "2020-04-09",
"2020-04-10", "2020-04-11", "2020-04-12", "2020-04-13", "2020-04-14",
"2020-04-15", "2020-04-16", "2020-04-17", "2020-04-18", "2020-04-19",
"2020-04-20", "2020-04-21", "2020-04-22", "2020-04-23", "2020-04-24",
"2020-04-25", "2020-04-26", "2020-04-27", "2020-04-28", "2020-04-29",
"2020-04-30", "2020-05-01", "2020-05-02", "2020-05-03", "2020-05-04",
"2020-05-05", "2020-05-06", "2020-05-07", "2020-05-08", "2020-05-09",
"2020-05-10", "2020-05-11", "2020-05-12", "2020-05-13", "2020-05-14",
"2020-05-15", "2020-05-16", "2020-05-17", "2020-05-18", "2020-05-19",
"2020-05-20", "2020-05-21", "2020-05-22", "2020-05-23", "2020-05-24",
"2020-05-25", "2020-05-26", "2020-05-27", "2020-05-28", "2020-05-29",
"2020-05-30", "2020-05-31", "2020-06-01", "2020-06-02", "2020-06-03",
"2020-06-04", "2020-06-05", "2020-06-06", "2020-06-07", "2020-06-08",
"2020-06-09", "2020-06-10", "2020-06-11", "2020-06-12", "2020-06-13",
"2020-06-14", "2020-06-15")
鉴于 date 是一个日期类或可计算的日期，这应该可以。
spndata <- data[data$iso_code == "ESP" & data$date > as.Date("2020-05-01") & data$date < as.Date("2020-06-01"),]