Get Subset from Data Frame

• salary$id
  • is one way to access a variable inside the data frame
• salary$id[1]
  • access first element of the vector
• alary$id[2:3]
  • access a subset of elements
• salary$id[c(5,7)]
  • access elements 5 and 7
• salary$id[ salary$[salary$startyr == 95]
  • all people join in 95
• salary[1,]
  • get the first row
• salary[,2]
  • get the second column
• salary[3:7, 2:4]
  • some rows and columns
• salary[, c("id","temp")]
  • extract columns by name
• yes = antibiotics[antibiotics$antib == 1, ]
  • put this subset into a new data frame

• select variables

Data1 <-ID_ICD9_Date1st_count_v2018_1M_random[,c(2,5,7,10:18,21)]

survdata_run <- dplyr::select(Data_Analysis, 1,3:9,17)

• random select records

Data1 <- Data1[sample(nrow(Data1), 50000), ]

Reference:

• R and Data Analysis, by [email protected]