Splitting coloumn with differing syntax in R - r

Question

I am having some trouble cleaning up my data. It consists of a list of sold houses. It is made up of the sell price, no. of rooms, m2 and the address.
As seen below the address is in one string.
Head(DF, 3)
Address Price m2 Rooms
Petersvej 1772900 Hoersholm 10.000 210 5
Annasvej 2B2900 Hoersholm 15.000 230 4
Krænsvej 125800 Lyngby C 10.000 210 5
A Mivs Alle 119800 Hjoerring 1.300 70 3
The syntax for the address coloumn is: road name, road no., followed by a 4 digit postalcode and the city name(sometimes two words).
Also need to extract the postalcode.. been looking at 'stringi' package haven't been able to find any examples..
any pointers are very much appreciated

Answer 1

1) Using separate in tidyr separate the subfields of Address into 3 fields merging anything left over into the last and then use separate again to split off the last 4 digits in the Number column that was generated in the first separate.
library(dplyr)
library(tidyr)
DF %>%
separate(Address, into = c("Road", "Number", "City"), extra = "merge") %>%
separate(Number, into = c("StreetNo", "Postal"), sep = -4)
giving:
Road StreetNo Postal City Price m2 Rooms CITY
1 Petersvej 77 2900 Hoersholm 10 210 5 Hoersholm
2 Annasvej 121B 2900 Hoersholm 15 230 4 Hoersholm
3 Krænsvej 12 5800 Lyngby C 10 210 5 C
2) Alternately, insert commas between the subfields of Address and then use separate to split the subfields out. It gives the same result as (1) on the input shown in the Note below.
DF %>%
mutate(Address = sub("(\\S.*) +(\\S+)(\\d{4}) +(.*)", "\\1,\\2,\\3,\\4", Address)) %>%
separate(Address, into = c("Road", "Number", "Postal", "City"), sep = ",")
Note
The input DF in reproducible form is:
DF <-
structure(list(Address = structure(c(3L, 1L, 2L), .Label = c("Annasvej 121B2900 Hoersholm",
"Krænsvej 125800 Lyngby C", "Petersvej 772900 Hoersholm"), class = "factor"),
Price = c(10, 15, 10), m2 = c(210L, 230L, 210L), Rooms = c(5L,
4L, 5L), CITY = structure(c(2L, 2L, 1L), .Label = c("C",
"Hoersholm"), class = "factor")), class = "data.frame", row.names = c(NA,
-3L))
Update
Added and fixed (2).

Answer 2

Check out the cSplit function from the splitstackshape package
library(splitstackshape)
df_new <- cSplit(df, splitCols = "Address", sep = " ")
#This will split your address column into 4 different columns split at the space
#you can then add an ifelse block to combine the last 2 columns to make up the city like
df_new$City <- ifelse(is.na(df_new$Address_4), as.character(df_new$Address_3), paste(df_new$Address_3, df_new$Address_4, sep = " "))

Answer 3

One way to do this is with regex.
In this instance you may use a simple regular expression which will match all alphabetical characters and space characters which lead to the end of the string, then trim the whitespace off.
library(stringr)
DF <- data.frame(Address=c("Petersvej 772900 Hoersholm",
"Annasvej 121B2900 Hoersholm",
"Krænsvej 125800 Lyngby C"))
DF$CITY <- str_trim(str_extract(DF$Address, "[a-zA-Z ]+$"))
This will give you the following output:
Address CITY
1 Petersvej 772900 Hoersholm Hoersholm
2 Annasvej 121B2900 Hoersholm Hoersholm
3 Krænsvej 125800 Lyngby C Lyngby C
In R the stringr package is preferred for regex because it allows for multiple-group capture, which in this example could allow you to separate each component of the address with one expression.