How to break datasets in r into new data sets using empty rows

Question

I am trying to "automize" the process of separating this data into datasets based on its trials. The original data is a list of values taken at several sites, and I want to break them into individual sets without having to use notation like c(1:312) because the number of rows in each trial vary. Each trail starts with a header, like d9, and ends with a blank row before the next header. How can I separate the data into new dataframes using the headers/empty rows?

This is for analyzing water data; Depth, Temperature, DO, and Salinity. The end goal is to create a graph of each trial showing the differences is Temperature across the trials.

Data Set (starting at row 1299)

1299 NA
1300 d4
1301 0.00
1302 0.18
1303 0.20
1304 0.31
1305 0.49
1306 0.76
1307 1.12
1308 1.51
1309 1.82
1310 1.92
1311 2.08
1312 2.35
1313 2.41
1314 2.48
1315 2.68
1316 2.97
1317 3.22
1318 3.33
1319 3.40
1320 3.55
1321 3.81
1322 4.05
1323 4.30
1324 4.41
1325 4.46
1326 4.56
1327 4.61
1328 4.62
1329 4.55
1330 4.54
1331 4.56
1332 4.49
1333 4.38
1334 4.38
1335 4.55
1336 4.71
1337 4.91
1338 5.14
1339 5.22
1340 5.26
1341 NA
1342 d11
1343 0.00
1344 0.22
1345 0.22
1346 0.27

D9 <- Data[3:314,]
D12 <- Data[317:517,]
D3 <- Data[520:703,]
D15 <- Data[706:795,]
D14 <- Data[798:853,]
D2 <- Data[856:939,]
D13 <- Data[942:975,]
D1 <- Data[978:1029,]
D6 <- Data[1032:1113,]
D5 <- Data[1116:1171,]
D7 <- Data[1174:1230,]
D8 <- Data[1233:1298,]
D4 <- Data[1301:1340,]
D11 <- Data[1343:1392,]
D10 <- Data[1395:1493,]

Answer 1

We can create a list using split along with grepl and cumsum

lst <- lapply(split.data.frame(x = df, cumsum(grepl('d\\d+',df$V2))), 
                function(x) {
                   names(x)[2] <- as.character(x[1,'V2'])
                   x <- x[-1,]
})

data

df <- structure(list(V1 = 1299:1346, V2 = c(NA, "d4", "0.00", "0.18", 
"0.20", "0.31", "0.49", "0.76", "1.12", "1.51", "1.82", "1.92", 
"2.08", "2.35", "2.41", "2.48", "2.68", "2.97", "3.22", "3.33", 
"3.40", "3.55", "3.81", "4.05", "4.30", "4.41", "4.46", "4.56", 
"4.61", "4.62", "4.55", "4.54", "4.56", "4.49", "4.38", "4.38", 
"4.55", "4.71", "4.91", "5.14", "5.22", "5.26", NA, "d11", "0.00", 
"0.22", "0.22", "0.27")), class = "data.frame", row.names = c(NA, -48L))

Note: It's advised to keep your data frames in a list instead of assigning them into Global env., see here