What is a regex to capture the total amount from strings? [closed] - ruby

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Closed 9 years ago.
I need to parse the total amount from different files. The layout of each file is different so the lines I need to parse vary.
What should be the regex for capturing from a sting a number that falls after "Total"?
It needs to be case insensitive and should consider the closest match after "Total". There can be anything before or after the word "Total", and I need the first number that comes after it.
For example:
from string "Service charges: 10 Total: 100 Shipping: 10"
from string "Service charges: 10 Total Amount: 100 Shipping: 10"
from string "Service charges: 10 Grand Total: 100 Shipping: 10"
from string "Service charges: 10 Total Amount (Rs.): 100 Shipping: 10"
The output should be 100 in all the above cases.

Answer 1

If all you're really asking about is a pattern match for various strings, look at using scan and grab the numeric strings:
[
"Service charges: 10 Total: 100 Shipping: 10",
"Service charges: 10 Total Amount: 100 Shipping: 10",
"Service charges: 10 Grand Total: 100 Shipping: 10",
"Service charges: 10 Total Amount (Rs.): 100 Shipping: 10",
].map{ |s| s.scan(/\d+/)[1] }
=> ["100", "100", "100", "100"]
This assumes you want the second number in each string.
If that order is going to change, which is unlikely because it looks like you're scanning invoices, then variations on the pattern and/or scan will work. This switches it up and uses a standard regex search based on the location of "Total", some possible intervening text, followed by ":" and the total value:
[
"Service charges: 10 Total: 100 Shipping: 10",
"Service charges: 10 Total Amount: 100 Shipping: 10",
"Service charges: 10 Grand Total: 100 Shipping: 10",
"Service charges: 10 Total Amount (Rs.): 100 Shipping: 10",
].map{ |s| s[/Total.*?: (\d+)/, 1] }
=> ["100", "100", "100", "100"]
To get the integer values append to_i inside the map statement:
[
"Service charges: 10 Total: 100 Shipping: 10",
"Service charges: 10 Total Amount: 100 Shipping: 10",
"Service charges: 10 Grand Total: 100 Shipping: 10",
"Service charges: 10 Total Amount (Rs.): 100 Shipping: 10",
].map{ |s| s[/Total.*?: (\d+)/, 1].to_i }
=> [100, 100, 100, 100]
For your example strings, it's probably preferable to use case-sensitive patterns to match "Total" unless you have knowledge that you will encounter "total" in lower-case. And, in that case, you should show such an example.

Answer 2

I think you can do this:
/Total[^:]*:\s+([0-9]+)/i
Explanation:
Total seach for "total"
[^:]* followed by anything or nothing until a colon ":" is found
:\s+ read over the colon and any following white space (maybe take * instead of +)
([0-9]+) read the numbers into a group for later retrieval -> 100
I am not sure how to indicate case insensitivity in the environment you use, but usually this can be done with some flags like I indicated with the i
here is a fiddle as an example

Answer 3

# assuming you have all your files ready in an array
a = ["Service charges: 10 Total: 100 Shipping: 10", "Service charges: 10 Total Amount: 100 Shipping: 10", "Service charges: 10 Grand Total: 100 Shipping: 10", "Service charges: 10 Total Amount (Rs.): 100 Shipping: 10"]
# we find every total with the following regexp
a.map {|s| s[/total[^\d]*(?<total>\d+)/i, 'total']}
#=> ["100", "100", "100", "100"]
The regexp is /total[^\d]*(?<total>\d*)/i. It looks for the word "total" and ignores any following character, until it finds a number (which it returns in a capture group). The i option makes it case insensitive.