####生成1948年1月-2011年11月的日期序列，要求是年-月格式，不要日

###先生成年月日格式的数据，然后再调整到指定的格式

temp <- seq.Date(from = as.Date("1948/01/01",format = "%Y/%m/%d"), by = "month", length.out = 767)

head(temp)

输出：[1] "1948-01-01" "1948-02-01" "1948-03-01" "1948-04-01" "1948-05-01" "1948-06-01"

tail(temp)

输出：[1] "2011-06-01" "2011-07-01" "2011-08-01" "2011-09-01" "2011-10-01" "2011-11-01"

temp <- format(temp, format = "%Y/%m")

head(temp)

输出：[1] "1948/01" "1948/02" "1948/03" "1948/04" "1948/05" "1948/06"