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11 Cards in this Set
- Front
- Back
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What is default data class for data read in R |
Data frame |
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Which function is used to list the variables in the workspace? |
ls() |
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How many dimensions does data frame have and which function is used to get how many cols and rows in it? |
Two dimensions dim() |
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dim() function returns [1] 5166 10 |
It means it has 5166 rows (observations) and 10 columns (variables) or nrow() to see how many rows in the dataset |
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Which function is used to check How much space the dataset is occupying |
object.size() |
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What does function names() do |
It returns a character vector of column (variables) names in the dataset |
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Which function is used to preview the top of the dataset? |
head() and shows you the first six rows of the data if you give only one argument but you can pass a second argument to see more rows in the data |
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Which function is used to preview the end of the dataset? |
tail() the same as head() function |
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What does NA mean in R ? |
It is placeholders for missing value. |
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categorical variables (what is the name in R) |
Factor variables Summary() displays the number of times each values (levels) occurs |
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Which function is used to see how many times each values occurs in the data in a factor variable? |
table(dataset$factor variable) |
