Add an algorithm that finds palindromes in text (#127)

Author: Ifeanyi55

text_manipulation/findPalindrome.R

@@ -0,0 +1,93 @@
+findPalindrome <- function(input) {
+  
+  is.palindrome <- function(input) {
+    if (is.numeric(input)) { # checks if input is numeric
+      # convert the numeric input value to character
+      input_con <- as.character(input)
+      # split the string into characters
+      input_split <- c(unlist(strsplit(input_con, split = "")))
+      # reverse the characters
+      input_rev <- rev(input_split)
+      # conditional statement to compare split string
+      # with the reversed string
+      if (all(input_split == input_rev) != TRUE) {
+        return(FALSE)
+      } else {
+        return(TRUE)
+      }
+    } else if (is.character(input)) { # checks if input is character
+      # split the string into characters
+      input_split <- c(unlist(strsplit(tolower(input), split = "")))
+      # reverse the characters
+      input_rev <- rev(input_split)
+      # conditional statement to compare split string
+      # with the reversed string
+      if (all(input_split == input_rev) != TRUE) {
+        return(FALSE)
+      } else {
+        return(TRUE)
+      }
+    }
+  }
+
+  if(is.character(input)) {
+    # clean out punctuation
+    input_clean <- tm::removePunctuation(input)
+    
+    # split the sentence into individual words
+    input_split <- c(unlist(strsplit(input_clean, split = " ")))
+    
+    # loop every word in the text through the is.palindrome() function
+    # and return their boolean values
+    check_palin <- c()
+    for (i in input_split) {
+      result <- is.palindrome(i)
+      check_palin <- append(check_palin, result)
+    }
+    
+    # check and return index positions of TRUE
+    indx <- which(check_palin == TRUE)
+    
+    # use the index positions to filter input_split
+    palindromes <- input_split[indx]
+    
+    # filter out words that contain less than one character
+    palin <- palindromes[nchar(palindromes) > 1]
+    
+    return(noquote(palin))
+    
+  } else if(is.numeric(input)) {
+    # convert numeric input to character
+    num_con <- as.character(input)
+    
+    # clean out punctuation
+    input_clean <- tm::removePunctuation(num_con)
+    
+    # split the sentence into individual words
+    input_split <- c(unlist(strsplit(input_clean, split = " ")))
+    
+    # loop every word in the text through the is.palindrome() function
+    # and return their boolean values
+    check_palin <- c()
+    for (i in input_split) {
+      result <- is.palindrome(i)
+      check_palin <- append(check_palin, result)
+    }
+    
+    # check and return index positions of TRUE
+    indx <- which(check_palin == TRUE)
+    
+    # use the index positions to filter input_split
+    palindromes <- input_split[indx]
+    
+    # filter out numbers that contain less than one character
+    palin <- palindromes[nchar(palindromes) > 1]
+    
+    return(noquote(palin))
+    
+  }
+}
+
+my_text <- "Bob works in a shop on a street called Pop. His work ID is 444, and his manager owns a racecar."
+
+findPalindrome(my_text)