Exercise 1: Extracting important info from filenames

You have a dataset and need to extract metadata for IL name, sun/shade treatment, and replicate number from the filenames:

filename.1 <- "a IL-9.2.4 crazy SH file rep1 name"
filename.2 <- "anotherIL-12.4sillySUfilerep20name"

You’d like to convert the filenames into IL-9.2.4,SH,rep1 and IL-12.4,SU,rep20, which can easily be split on the delimiting comma with strsplit().

Extract this metadata using sub() followed by strsplit to split the resulting string. You will need to make use of three capture groups.

Exercise 2: Character conversions

In last week’s exercise #2, you were asked to replace all of the “i”s in state names with “y”s. Using gsub("i", "y", state.name, ignore.case = T) accomplished that task, but resulted in state names beginning with lower case “y”s.

There is another (non-regex) function that can be used instead: chartr() does character translations from one characer to another. To convert all “i”s to “y”s and all “I”s to “Y”s in the state names, we can use the following:

data(state)
chartr("Ii", "Yy", state.name)

##  [1] "Alabama"        "Alaska"         "Aryzona"        "Arkansas"      
##  [5] "Calyfornya"     "Colorado"       "Connectycut"    "Delaware"      
##  [9] "Floryda"        "Georgya"        "Hawayy"         "Ydaho"         
## [13] "Yllynoys"       "Yndyana"        "Yowa"           "Kansas"        
## [17] "Kentucky"       "Louysyana"      "Mayne"          "Maryland"      
## [21] "Massachusetts"  "Mychygan"       "Mynnesota"      "Myssyssyppy"   
## [25] "Myssoury"       "Montana"        "Nebraska"       "Nevada"        
## [29] "New Hampshyre"  "New Jersey"     "New Mexyco"     "New York"      
## [33] "North Carolyna" "North Dakota"   "Ohyo"           "Oklahoma"      
## [37] "Oregon"         "Pennsylvanya"   "Rhode Ysland"   "South Carolyna"
## [41] "South Dakota"   "Tennessee"      "Texas"          "Utah"          
## [45] "Vermont"        "Vyrgynya"       "Washyngton"     "West Vyrgynya" 
## [49] "Wysconsyn"      "Wyomyng"

Sidenote: two other non-regex functions used to convert text are tolower() and toupper():

x <- "Oh my.... Look over there!"
tolower(x)

## [1] "oh my.... look over there!"

toupper(x)

## [1] "OH MY.... LOOK OVER THERE!"

Your task: You want to look cool, so use two of these functions to convert the state names such that all vowells are uppercase and all consonants are lower case.