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everybody. I hope that you would help me to solve my query. For a vector representing the price ($) of apples say,

apple <- c(23, 26, 54, 34, 34, 34, 98, 23, 4, 34, 098, 45, 93, 20, 39, 83, 78, 34, 09, 8, 56, 98, 99, 62, 29)

I can assign a factor vector that represents whether it is "cheap" if apples cost less than $50 and "expensive" if apple cost more than or equal to $50. For instance, the factor variable could easily be assigned as: 

price <- factor(apple>50, labels = c("cheap", "expensive"))

However, I am clueless of assigning a factor variable with three levels of price say cheap, moderate, and expensive, say when apples are said to be of a moderate price if they cost between $30 and $40. Thank you

Martin Gal
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Pankaj
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2 Answers2

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We can use cut:

 cut(apple, breaks = c(0, 30, 40, Inf), labels = c("Cheap", "Moderate", "Expensive"))
#>  [1] Cheap     Cheap     Expensive Moderate  Moderate  Moderate  Expensive Cheap    
#>  [9] Cheap     Moderate  Expensive Expensive Expensive Cheap     Moderate  Expensive
#> [17] Expensive Moderate  Cheap     Cheap     Expensive Expensive Expensive Expensive
#> [25] Cheap    
#> Levels: Cheap Moderate Expensive
Allan Cameron
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  • Very nice solution. You could replace `100` with `Inf` in case of very expensive apples. ;-) – Martin Gal Jun 07 '20 at 17:26
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    Thanks @MartinGal I just realised that made more sense. I guess you could also make the lower value -Inf if anyone wanted to give money away with their apples! – Allan Cameron Jun 07 '20 at 17:28
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We can use findInterval in base R 

c('Cheap', 'Moderate', 'Expensive')[findInterval(apple, c(0, 30, 40))]
#[1] "Cheap"     "Cheap"     "Expensive" "Moderate"  "Moderate"  "Moderate"  "Expensive" "Cheap"     "Cheap"     "Moderate"  "Expensive"
#[12] "Expensive" "Expensive" "Cheap"     "Moderate"  "Expensive" "Expensive" "Moderate"  "Cheap"     "Cheap"     "Expensive" "Expensive"
#[23] "Expensive" "Expensive" "Cheap"
akrun
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