regular expression help in R

Question

I have data that looks like this, where the negative sign is a suffix at the end of the numeric.

"general_amount"
"0000000441244"
"0000000127769-"
"0000000043819"
"0000000522600-"

Can someone help me find a regular expression to produce the desired output below.

"general_amount"
 441244
-127769
 43819
-522600

Answer 1

sub('^0*([^-]*)(-?)$', '\\2\\1', x)

## [1] "general_amount" "441244"         "-127769"        "43819"          "-522600"

^0* matches all leading 0 characters.
[^-]* matches all non- - characters.
-? matches zero or one - character.
Finally, the $ matches the end of the string.

The middle two pieces are captured with () , as \\\\1 and \\\\2 , and printed in reverse order.

Answer 2

Using gsub , with another idea.

The idea is to divide the input into 3 elements

1. series of 0 :(^0+)
2. series of number :([0-9]+)

3. find the '-' 1 or zero times : (-?)"

     as.numeric(gsub("(^0+)([0-9]+)(-?)","\\\\3\\\\2",tt)) [1] 441244 -127769 43819 -522600 

Answer 3

Dude it took me 3 hours to find answer to your question

sed -re 's/[^a-zA-Z0-9]0+([0-9]+)(-?)/\2\1/g' anyfile.txt 

But in the end i did it. May have some short coming but i got it nearly