R Programming · all questions

Data Structures in R Programming
practice.

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Q101

readlines is used for . . . . . . . .

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Q102

Which of the following R code extracts the second column for the following matrix?

> x <- matrix(1:6, 2, 3)

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Q103

What will be the output of the following R code?

> x <- matrix(1:6, 2, 3)
> x[1, , drop = FALSE]

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Q104

The . . . . . . . . operator allows you to string operations in a left-to-right fashion.

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Q105

Point out the correct statement?

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Q106

dplyr can be integrated with the . . . . . . . . package for large fast tables.

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Q107

What will be the output of the following R code?

> x <- list(foo = 1:4, bar = 0.6, baz = "hello")
> name <- "foo"
> x$name

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Q108

Point out the wrong statement?

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Q109

. . . . . . . . extract a subset of rows from a dataframe based on logical conditions.

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Q110

Which of the following statement would read file "foo.txt"?

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Q111

Which of the following function gives the day of the week?

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Q112

Point out the wrong statement?

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Q113

What will be the output of the following R code?

> x <- as.POSIXct("2012-10-25 01:00:00")
> y <- as.POSIXct("2012-10-25 06:00:00", tz = "GMT")
> y-x

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Q114

What will be the output of the following R code?

> x <- list(foo = 1:4, bar = 0.6, baz = "hello")
> name <- "foo"
> x[[name]]

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Q115

What will be the output of the following R code?

> datestring <- c("January 10, 2012 10:40", "December 9, 2011 9:10")
> x <- strptime(datestring, "%B %d, %Y %H:%M")
> x

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Q116

We can dump() R objects to a file by passing . . . . . . . .

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Q117

What will be the output of the following R code?

> x <- 1:4
> y <- 6:9
> x/y

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Q118

Point out the correct statement?

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Q119

The dplyr package can be installed from CRAN using . . . . . . . .

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Q120

Which of the following argument denotes if the file has a header line?

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