Extract specific values (n digit long and starting with a number)

user_11974875 0
Viewed 85

I have csv file like this:

  X      a      b      c      d      e      f
1 1 663583 364950 651551 691428 111738  14522
2 2 373345 273164     79  65979 753131 446762
3 3 481865 920656 510754  67696 987635 964008
4 4 132506 824874 917557 506235 235523 500492
5 5  59034 772322 195845 130662 828260 262721
6 6 129712 294165 867589 199928 434893 444084

I need a list of values starting with 7 and length of 6

for the example abve I expect:

[753131,772322]

I saw some using of grepl() function but could not figure out how to extract the values and turn them into a list.

grepl apply dataframe r
3 Answers

Using regex

d[sapply(d, function(x) grepl("^7", x) & nchar(x) == 6)]
#[1] 772322 753131

Or Math

d[trunc(d/10^5) == 7]
#[1] 772322 753131

DATA

d = read.table(strip.white = TRUE, stringsAsFactors = FALSE, header = TRUE,
               text =
"  X      a      b      c      d      e      f
 1 1 663583 364950 651551 691428 111738  14522
 2 2 373345 273164     79  65979 753131 446762
 3 3 481865 920656 510754  67696 987635 964008
 4 4 132506 824874 917557 506235 235523 500492
 5 5  59034 772322 195845 130662 828260 262721
 6 6 129712 294165 867589 199928 434893 444084")
user_71289340

An option is also to unlist and use grep by matching the digit 7 at the start (^) of the string followed by 5 more digits (\\d{5}) before the end ($) of the string

unname(grep("^7\\d{5}$", unlist(df1), value = TRUE))
#[1] "772322" "753131"

If we want to get the values by row, then transpose the dataset, concatenate to a vector and use grep

unname(grep("^7\\d{5}$", c(t(df1)), value = TRUE))
#[1] "753131" "772322"

data

df1 <- structure(list(X = 1:6, a = c(663583L, 373345L, 481865L, 132506L, 
59034L, 129712L), b = c(364950L, 273164L, 920656L, 824874L, 772322L, 
294165L), c = c(651551L, 79L, 510754L, 917557L, 195845L, 867589L
), d = c(691428L, 65979L, 67696L, 506235L, 130662L, 199928L), 
    e = c(111738L, 753131L, 987635L, 235523L, 828260L, 434893L
    ), f = c(14522L, 446762L, 964008L, 500492L, 262721L, 444084L
    )), class = "data.frame", row.names = c("1", "2", "3", "4", 
"5", "6"))
user_37322710 
d<-as.list(d[d >=700000 & d< 799999])
user_112035830
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