如何在數據幀中基於中的R

Question

在另一個值I想之前p => 1，以提取的在數據幀中的第一行在C的值，以及提取的一列的值作爲d的值在數據幀的第一行時爲p => 1。

然後我想下一個後續行中，以確定Ç和d的值時p再次下降< 1。我正在努力知道如何做到這一點。任何意見，將不勝感激。

> dput(df) 
structure(list(p = c(0.00032, 0.0045, 0.01, 0.34, 0.5576, 0.89, 
1.00238, 1.2356, 4.76, 18.96, 23.56, 34.005, 26.778, 16.543, 
12.3276, 5.674, 3.45, 1.987, 0.976, 0.5629, 0.34564, 0.034, 0.0123, 
0.0023), c = c("23/10/2016 15:23:34", "23/10/2016 15:23:44", 
"23/10/2016 15:23:54", "23/10/2016 15:24:04", "23/10/2016 15:24:14", 
"23/10/2016 15:24:24", "23/10/2016 15:24:34", "23/10/2016 15:24:44", 
"23/10/2016 15:24:54", "23/10/2016 15:25:04", "23/10/2016 15:25:14", 
"23/10/2016 15:25:24", "23/10/2016 15:25:34", "23/10/2016 15:25:44", 
"23/10/2016 15:25:54", "23/10/2016 15:26:04", "23/10/2016 15:26:14", 
"23/10/2016 15:26:24", "23/10/2016 15:26:34", "23/10/2016 15:26:44", 
"23/10/2016 15:26:54", "23/10/2016 15:27:04", "23/10/2016 15:27:14", 
"23/10/2016 15:27:24"), d = c(324.5, 234.5, 109.5, 236.4, 86.5, 
67.8, 126.4, 139.8, 139.8, 145.6, 257.6, 309, 19.4, 359.5, 299.5, 
234.5, 134.5, 136.7, 135.7, 138.9, 223.1, 256.7, 295.6, 312.8 
)), .Names = c("p", "c", "d"), class = "data.frame", row.names = c(NA, 
-24L)) 

> df 
      p     c  d 
1 0.00032 23/10/2016 15:23:34 324.5 
2 0.00450 23/10/2016 15:23:44 234.5 
3 0.01000 23/10/2016 15:23:54 109.5 
4 0.34000 23/10/2016 15:24:04 236.4 
5 0.55760 23/10/2016 15:24:14 86.5 
6 0.89000 23/10/2016 15:24:24 67.8 
7 1.00238 23/10/2016 15:24:34 126.4 
8 1.23560 23/10/2016 15:24:44 139.8 
9 4.76000 23/10/2016 15:24:54 139.8 
10 18.96000 23/10/2016 15:25:04 145.6 
11 23.56000 23/10/2016 15:25:14 257.6 
12 34.00500 23/10/2016 15:25:24 309.0 
13 26.77800 23/10/2016 15:25:34 19.4 
14 16.54300 23/10/2016 15:25:44 359.5 
15 12.32760 23/10/2016 15:25:54 299.5 
16 5.67400 23/10/2016 15:26:04 234.5 
17 3.45000 23/10/2016 15:26:14 134.5 
18 1.98700 23/10/2016 15:26:24 136.7 
19 0.97600 23/10/2016 15:26:34 135.7 
20 0.56290 23/10/2016 15:26:44 138.9 
21 0.34564 23/10/2016 15:26:54 223.1 
22 0.03400 23/10/2016 15:27:04 256.7 
23 0./10/2016 15:27:14 295.6 
24 0.00230 23/10/2016 15:27:24 312.8 

所需的輸出值：

c_1     d_1 c_2     d_2 
23/10/2016 15:24:24 126.4 23/10/2016 15:26:34 135.7 

Answer 1

不是最完美的解決方案，但它的工作：

indices <- which(df$p >= 1) 

c(c_1 = df[min(indices)-1,]$c, 
    d_1 = df[min(indices),]$d, 
    c_2 = df[max(indices)+1,]$c, 
    d_2=df[max(indices)+1,]$d)