3.1 A Data Frame as a Dataset
20210103 A data frame is essentially a rectangular table
(or matrix) of data consisting of rows (observations) and
columns (variables). We can
base::print.data.frame() to view a table, here choosing the
first 10 observations of the first 6 variables of the ds
dataset.
## date location min_temp max_temp rainfall evaporation
## 1 2008-12-01 Albury 13.4 22.9 0.6 NA
## 2 2008-12-02 Albury 7.4 25.1 0.0 NA
## 3 2008-12-03 Albury 12.9 25.7 0.0 NA
## 4 2008-12-04 Albury 9.2 28.0 0.0 NA
## 5 2008-12-05 Albury 17.5 32.3 1.0 NA
## 6 2008-12-06 Albury 14.6 29.7 0.2 NA
## 7 2008-12-07 Albury 14.3 25.0 0.0 NA
## 8 2008-12-08 Albury 7.7 26.7 0.0 NA
## 9 2008-12-09 Albury 9.7 31.9 0.0 NA
## 10 2008-12-10 Albury 13.1 30.1 1.4 NAAlternatively we might sample 10 random observations (dplyr::sample_n()) of 5 random variables (dplyr::select()):
# Display a random selection of observations and variables.
ds %>%
sample_n(10) %>%
select(sample(1:ncol(ds), 5)) %>%
print.data.frame()## humidity_3pm min_temp wind_gust_speed max_temp rainfall
## 1 75 11.5 39 16.8 20.2
## 2 68 13.6 59 17.9 8.2
## 3 23 21.0 74 34.1 0.0
## 4 54 15.9 46 26.0 6.8
## 5 43 1.8 22 20.0 0.0
## 6 36 9.9 43 26.8 0.0
## 7 16 18.9 39 28.2 0.0
## 8 40 12.9 35 31.0 0.0
## 9 12 6.5 37 32.2 0.0
## 10 44 10.2 46 18.4 0.4This tabular form (i.e., it has rows and columns) is common for data science and we refer to it as our dataset.
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