R - 提取子字符串

Question

I have a column with list of names which includes their Title.

Example:

Ryerson, Master. John Borie
Corey, Mrs. Percy C (Mary Phyllis Elizabeth Miller)

I would like to extract their Titles from their names ie, Mr, Mrs, Master etc

Function:

In[79]:
mystring="Wilkes, Master. James (Ellen Needs)"
In[80]:
substr(sub(".*,", "", mystring),2,which(strsplit(sub(".*,", "", mystring),"")[[1]]==".")-1)
Out[80]:
[1] "Master"

When I test the above function on one name, it works fine. But, when I apply the same function to the column with list of names, it is extracting only two characters.

Example: Ryerson, Master. John Borie

I would like to see 'Master' extracted from this name whereas I see 'Ma'.

[436] "Mi" "Mi" "Mr" "Mr" "Mr" "Mr" "Mr" "Mr" "Ms" "Mr" "Ma" "Mi" "Mr" "Mi" "Ma"

I don't know what's wrong with the function. Appreciate your help!

Answer 1

Based on the example showed, we can match one or more characters that are not a , ( [^,]+ ) followed by , and one or more space ( \\\\s+ ) from the beginning ( ^ ) of the string or | a dot ( \\\\. ) followed by any character till the end of the string ( .* ) and replace it with '' .

gsub("^[^,]+,\\s+|\\..*$", "", str1)
#[1] "Master" "Mrs"  

If it is the second 'word', then word can be used

library(stringr)
word(str1, 2)
#[1] "Master." "Mrs."   

data

str1 <- c("Ryerson, Master. John Borie", 
       "Corey, Mrs. Percy C (Mary Phyllis Elizabeth Miller)")

Answer 2

If you have any spaces in the vector containing names eg:Mr. Mahesh, you can try this code

my <- c("MR. Arun", "Master. mahesh")
y <- do.call(rbind,strsplit(my," "))
z <- y[,1]
print(z)
[1] "MR."     "Master."