R: Comparing Text Similarity between Neighbour Strings

Question

I am trying to compare texts in a column to identify the text similarity, in terms of whether adjacent letters in the texts are similar; how many substition is necessary for two adjacent letters to make the both letters same.

Example: JANE-JNAE (1 - AN/NA), MARY-MART(0), CLERA-LCREA(2 - CL/LC & ER/RE)

I have tried stringdist methods but they do not provide solutions for my problem.

Since I am new to R, I could not write an efficent code to show here:

substition <- function(text1,tex2){

  if(text1 == text2){
    return(TRUE)
  }

  if(nchar(text1) != nchar(text2)){
    return(FALSE)
  }

  vec1 <- strsplit("text1",split="")[[1]]
  vec2 <- strsplit("text2",split="")[[1]]

(can't go on)

. But to illustrate:

data is something like this

df$NO  df$names
1      JANE
2      MARY
3      CLERA
4      JNAE
5      LCREA
6      MART

and the desired output is:

df$NO  df$names df$substition
1      JANE     1
2      MARY     0
3      CLERA    2
4      JNAE     1
5      LCREA    2
6      MART     0

Answer 1

You can use the Levenshtein distance (https://en.wikipedia.org/wiki/Levenshtein_distance) between strings. The distance gives the minimal number of insertions, deletions and substitutions needed to transform one string into another.

Usage

adist(
  c("lazy", "lasso", "lassie"),
  c("lazy", "lazier", "laser")
)

Returns a 3x3 matrix of distances:

##      [,1] [,2] [,3]
## [1,]    0    3    3
## [2,]    3    4    2
## [3,]    4    3    3