提取两个字符之间的 提取第一个|和第二个|中间的 stringr

library(stringr)

# Assuming anno$major.protein.id is a vector of strings
pattern <- "(?<=\\|).*?(?=\\|)"

# Function to extract text between first two "|" characters
extract_text_between_pipes <- function(input_string) {
  extracted_text <- str_extract(input_string, pattern)
  return(ifelse(is.na(extracted_text), NA, extracted_text))
}

# Use lapply to extract text from all elements in anno$major.protein.id
extracted_texts <- lapply(anno$major.protein.id, extract_text_between_pipes)

# Get the length of extracted_texts
num_extracted_texts <- length(extracted_texts)