how to erase several characters in a cell? [closed] - r

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I would like to erase characters "(B)" in the code column, so then I could do "summarise" the 'stock_needed'. My data looks like this.
code stock_need
(B)1234 200
(B)5678 240
1234 700
5678 200
0123 200
to be like this.
code stock_need
1234 200
5678 240
1234 700
5678 200
0123 200
How could these "(B)" erased? Thanx in advance

Answer 1

What are other patterns your data has? If it's always "(B)" you can do
sub("\\(B\\)", "", df$code)
#[1] "1234" "5678" "1234" "5678" "0123"
Or if it could be any character do
sub("\\([A-Z]\\)", "", df$code)
You could also extract only the numbers from Code
sub(".*?(\\d+).*", "\\1", df$code)
You might want to wrap output of sub in as.numeric or as.integer to get numeric/integer output.
We can also use readr
readr::parse_number(df$code)

Answer 2

Basically, you need to do two things:
remove the unnecessary part of the string
convert the string to numeric.
Say, we load your data frame:
df <- read.table(header=TRUE, text="code stock_need
(B)1234 200
(B)5678 240
1234 700
5678 200
0123 200 ")
First, we replace the column "code" with something without the parentheses:
df$code <- gsub("\\(B\\)", "", df$code)
Explanation: why the weird \\? Because if we wrote (B), gsub would treat the parentheses in a special way. Parentheses have a special meaning in regular expressions, and the first argument to gsub is a regular expression.
Next, we make a number vector out of it:
df$code <- as.numeric(df$code)