Need to create data frame from patterns in a string

Question

I have the following string I need to extract the patterns into a single column data frame named SIZE

str <- "N · 0.1 [mm]: N · 0.1 + 0.02 [mm]: N · 0.1 + 0.05 [mm] N · 0.1 + 0.08 [mm] M · 1 [mm]: M · 1 + 0.5 [mm] M · 1 + 0.75 [mm]"

The patterns are either followed by : or whitespace and always ends in [mm]

The regex I am using to match my patterns is and it works, but i'm not sure how to extract the matches to create a column as a data frame.

\S\W+\d\.?\d?\s\+?\s?\d?\.?\d?\d?\s?\[mm\]

Output expected: 1 column named SIZE

       N · 0.1 [mm]
N · 0.1 + 0.02 [mm]
N · 0.1 + 0.05 [mm]
N · 0.1 + 0.08 [mm]
         M · 1 [mm]
   M · 1 + 0.5 [mm]
  M · 1 + 0.75 [mm]

Any help appreciated. Thanks..

hwnd · Accepted Answer · 2013-12-04 16:33:06Z

5

Perhaps, strsplit would make things easier here..

str  <- "N · 0.1 [mm]: N · 0.1 + 0.02 [mm]: N · 0.1 + 0.05 [mm] N · 0.1 + 0.08 [mm] M · 1 [mm]: M · 1 + 0.5 [mm] M · 1 + 0.75 [mm]"
vals <- strsplit(str, '(?<=\\])[\\s:]*', perl = T)
data.frame(SIZE = unlist(vals))

Output

                 SIZE
1        N · 0.1 [mm]
2 N · 0.1 + 0.02 [mm]
3 N · 0.1 + 0.05 [mm]
4 N · 0.1 + 0.08 [mm]
5          M · 1 [mm]
6    M · 1 + 0.5 [mm]
7   M · 1 + 0.75 [mm]

answered Dec 4, 2013 at 16:33

hwnd

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1 Comment

A5C1D2H2I1M1N2O1R2T1 Over a year ago

Because of the relationship between data.frames and lists in R, data.frame(setNames(strsplit(str, '(?<=\\])[\\s:]*', perl = T), "SIZE")) would also work. +1

A5C1D2H2I1M1N2O1R2T1 · Accepted Answer · 2013-12-04 16:31:24Z

2

Here's one approach to get the data in: replace any instances of "[mm] " with "[mm]: " and scan the text in with ":" as your separator. No fussing with regexes....

scan(what = "", text = gsub("[mm] ", "[mm]: ", str, fixed=TRUE), 
     sep = ":", strip.white=TRUE)
# Read 7 items
# [1] "N · 0.1 [mm]"        "N · 0.1 + 0.02 [mm]" "N · 0.1 + 0.05 [mm]"
# [4] "N · 0.1 + 0.08 [mm]" "M · 1 [mm]"          "M · 1 + 0.5 [mm]"   
# [7] "M · 1 + 0.75 [mm]"

Just assign the result there to a column in a data.frame or create a data.frame with the output. Or, all in one:

data.frame(
  SIZE = scan(text = gsub("[mm] ", "[mm]: ", str, fixed=TRUE), 
              sep = ":", strip.white=TRUE, what = ""))

answered Dec 4, 2013 at 16:31

A5C1D2H2I1M1N2O1R2T1

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