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# 103.1.5 R Data Frames

A data frame is a common way for storing data in R. We can create data frames using function data.frame

Here are four vectors of the same length,

```  >Name<-c("Rick","Nick","Harry")
>Age<-c(15,17,19)
>English<-c(12,13,20)
>Maths<-c(20,23,21)```

A data frame, students has been created using the individual vectors Name, Age, English, and Maths.

``` >students<-data.frame(Name,Age,English,Maths)
>students
Name Age English Maths
1 Rick 15 12 20
2 Nick 17 13 23
3 Harry 19 20 21```
`````` >Profile_data <- data.frame(Name, Age)
>Profile_data``````
Name Age
1 Rick 15
2 Nick 17
3 Harry 19

``````
`````` >students1 <-c(Name, Age, English, Maths)
>students1
``` [1] "Rick" "Nick" "Harry" "15" "17" "19" "12" "13" "20" "20" "23"
[12] "21"```

``` ```Accessing a Data Frame

To access each column of a data frame, we use ‘\$’. We write it as- Dataset\$column

``` students\$Name

[1] Rick Nick Harry
Levels: Harry Nick Rick```

We have other ways-

``` >students\$English
[1] 12 13 20```
``` >students["Name"]
Name
1 Rick
2 Nick
3 Harry

>students[1,]
Name Age English Maths
1 Rick 15 12 20```
``` >students[,1]
[1] Rick Nick Harry
Levels: Harry Nick Rick```
``` >students[,2:4]
Age English Maths
1 15 12 20
2 17 13 23
3 19 20 21```
``` >students[,-1]
Age English Maths
1 15 12 20
2 17 13 23
3 19 20 21```
``` >students[-1,]
Name Age English Maths
2 Nick 17 13 23
3 Harry 19 20 21```
``` >students[,c(1,4)]
Name Maths
1 Rick 20
2 Nick 23
3 Harry 21```

There is a slight Difference in Accessed Data frame elements in these commands.

``` >students\$Name
[1] Rick Nick Harry
Levels: Harry Nick Rick```

``` >students["Name"]
Name
1 Rick
2 Nick
3 Harry```

``` >students[,1]
[1] Rick Nick Harry
Levels: Harry Nick Rick```

Built-in DataFrames

When we install R, then R comes with built-in Datasets. These are some of the useful open source datasets for practice. We can call them by command: data()

``` data()
#Air Passengers data
AirPassengers```
```Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
## 1949 112 118 132 129 121 135 148 148 136 119 104 118
## 1950 115 126 141 135 125 149 170 170 158 133 114 140
## 1951 145 150 178 163 172 178 199 199 184 162 146 166
## 1952 171 180 193 181 183 218 230 242 209 191 172 194
## 1953 196 196 236 235 229 243 264 272 237 211 180 201
## 1954 204 188 235 227 234 264 302 293 259 229 203 229
## 1955 242 233 267 269 270 315 364 347 312 274 237 278
## 1956 284 277 317 313 318 374 413 405 355 306 271 306
## 1957 315 301 356 348 355 422 465 467 404 347 305 336
## 1958 340 318 362 348 363 435 491 505 404 359 310 337
## 1959 360 342 406 396 420 472 548 559 463 407 362 405
## 1960 417 391 419 461 472 535 622 606 508 461 390 432```

Cars data set is included with car speed and stopping distance.

```#cars data
cars```
``` ##    speed dist
## 1      4    2
## 2      4   10
## 3      7    4
## 4      7   22
## 5      8   16
## 6      9   10
## 7     10   18
## 8     10   26
## 9     10   34
## 10    11   17
## 11    11   28
## 12    12   14
## 13    12   20
## 14    12   24
## 15    12   28
## 16    13   26
## 17    13   34
## 18    13   34
## 19    13   46
## 20    14   26
## 21    14   36
## 22    14   60
## 23    14   80
## 24    15   20
## 25    15   26
## 26    15   54
## 27    16   32
## 28    16   40
## 29    17   32
## 30    17   40
## 31    17   50
## 32    18   42
## 33    18   56
## 34    18   76
## 35    18   84
## 36    19   36
## 37    19   46
## 38    19   68
## 39    20   32
## 40    20   48
## 41    20   52
## 42    20   56
## 43    20   64
## 44    22   66
## 45    23   54
## 46    24   70
## 47    24   92
## 48    24   93
## 49    24  120
## 50    25   85```

This is about Dataframes. Next data type is the list.