Question

我正在尝试查找已知字符串之后的字符串： string_n = 1 .... 因此，我尝试确定索引“ n =”，然后找出它的实验次数（在本例中为1）。我该怎么做？到目前为止，这是我的方法，但无法正常工作，我无法获得exp_number的值：

library(stringr)

for (i in length(names)){

  pos_of_n = str_which(pattern = '=', names[i], fixed = TRUE)

  substring = names[I]

  exp_number = substring[pos_of_n[1]+1]

  exp_name <- paste("exp", toString(exp_number,width=NULL))

}

Answer 1

我假设您的数据看起来像下面的字符串。

library(stringr)
strings <- c('exp n=1', 'exp n=2 more information...')

# Returns a matrix. First column is complete match, second the first
# set of parentheses, third the second set of parentheses -- which is
# the one we want.
exp_numbers <- str_match(strings, '(n\\=)(\\d+)')[,3]
# [1] "1" "2"
paste0("Exp", exp_numbers)
# [1] "Exp1" "Exp2"

# Using the data string you provided
strings <- c(' D:Maj_stats_n1_pooled2019-0918_screen_n=3_T_Template.csv')
exp_numbers <- stringr::str_match(strings, '(n\\=)(\\d+)')[,3]
labels <- paste0("Exp", exp_numbers)
labels
#> [1] "Exp3"

根据索引查找字符串

1 个答案: