Keep only rows if number is greater than... in specific column - r

Question

This is an example of data:
exp_data <- structure(list(Seq = c("AAAARVDS", "AAAARVDSSSAL",
"AAAARVDSRASDQ"), Change = structure(c(19L, 20L, 13L), .Label = c("",
"C[+58]", "C[+58], F[+1152]", "C[+58], F[+1152], L[+12], M[+12]",
"C[+58], L[+2909]", "L[+12]", "L[+370]", "L[+504]", "M[+12]",
"M[+1283]", "M[+1457]", "M[+1491]", "M[+16]", "M[+16], Y[+1013]",
"M[+16], Y[+1152]", "M[+16], Y[+762]", "M[+371]", "M[+386], Y[+12]",
"M[+486], W[+12]", "Y[+12]", "Y[+1240]", "Y[+1502]", "Y[+1988]",
"Y[+2918]"), class = "factor"), `Mass` = c(1869.943,
1048.459, 707.346), Size = structure(c(2L, 2L, 2L), .Label = c("Matt",
"Greg",
"Kieran"
), class = "factor"), `Number` = c(2L, 2L, 2L)), row.names = c(244L,
392L, 396L), class = "data.frame")
I would like to bring your attention to column name Change as this is the one which I would like to use for filtering. We have three rows here and I would like to keep only first one because there is a change bigger than 100 for specific letter. I would like to keep all of the rows which contain the change of letter greater than +100. It might be a situatation that there is up to 4-5 letters in change column but if there is at least one with modification of at least +100 I would like to keep this row.
Do you have any simple solution for that ?
Expected output:
Seq Change Mass Size Number
244 AAAARVDS M[+486], W[+12] 1869.943 Greg 2

Answer 1

Not entirely sure I understood your problem statement correctly, but perhaps something like this
library(dplyr)
library(stringr)
exp_data %>% filter(str_detect(Change, "\\d{3}"))
# Seq Change Mass Size Number
#1 AAAARVDS M[+486], W[+12] 1869.943 Greg 2
Or the same in base R
exp_data[grep("\\d{3}", exp_data$Change), ]
# Seq Change Mass Size Number
#1 AAAARVDS M[+486], W[+12] 1869.943 Greg 2
The idea is to use a regular expression to keep only those rows where Change contains at least one three-digit expression.

Answer 2

You can use str_extract_all from the stringr package
library(stringr)
data.table solution
library(data.table)
setDT(exp_data)
exp_data[, max := max(as.numeric(str_extract_all(Change, "[[:digit:]]+")[[1]])), by = Seq]
exp_data[max > 100, ]
Seq Change Mass Size Number max
1: AAAARVDS M[+486], W[+12] 1869.9 Greg 2 486
dplyr solution
library(dplyr)
exp_data %>%
group_by(Seq) %>%
filter(max(as.numeric(str_extract_all(Change, "[[:digit:]]+")[[1]])) > 100)
# A tibble: 1 x 5
# Groups: Seq [1]
Seq Change Mass Size Number
<chr> <fct> <dbl> <fct> <int>
1 AAAARVDS M[+486], W[+12] 1870. Greg 2