How to find the Index of Last Occurrence of Substring in R - Step by Step Examples

How to find the Index of Last Occurrence of Substring in R ?

Answer

To find the index of the last occurrence of a substring in R, you can use the `gregexpr` function along with the `tail` and `unlist` functions to extract the last occurrence's index from the result.

✐ Examples

1 Find Index of Last Occurrence in String

In this example,

We create a string named `str` with a desired string value.
We use the `gregexpr` function along with the substring pattern and `tail` and `unlist` functions to extract the positions of all occurrences of the substring in `str`.
We then extract the last position from the result using indexing.
Finally, we print or use the last index as needed.

R Program

str <- "hello hello world"
substring <- "hello"
positions <- gregexpr(substring, str)[[1]]
last_index <- tail(positions, 1)
print(last_index)

Output

[1] 7

2 Find Index of Last Occurrence in Another String

In this example,

We create two string variables named `str1` and `str2` with different values.
We use the `gregexpr` function along with `tail` and `unlist` to extract the positions of all occurrences of `str2` in `str1`.
We then extract the last position from the result using indexing.
Finally, we print or use the last index as needed.

R Program

str1 <- "apple banana cherry banana"
str2 <- "banana"
positions <- gregexpr(str2, str1)[[1]]
last_index <- tail(positions, 1)
print(last_index)

Output

[1] 21

Summary

In this tutorial, we learned How to find the Index of Last Occurrence of Substring in R language with well detailed examples.

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How to find the Index of Last Occurrence of Substring in R - Step by Step Examples

How to find the Index of Last Occurrence of Substring in R ?

Answer

✐ Examples

1 Find Index of Last Occurrence in String

R Program

Output

2 Find Index of Last Occurrence in Another String

R Program

Output

Summary

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