Hello,
I was wondering if someone could tell me where
I'm going wrong with my regular expression. I'm
trying to write a regexp that identifies whether
a string contains a correctly-formatted currency
amount. I want to support dollars, UK pounds and
Euros, but the example below deliberately omits
Euros in case the Euro symbol get mangled
anywhere in email or listserver processing. I
also want people to be able to omit the currency symbol if they wish.
My regexp that I'm matching against is: "^\$\£?\d{0,10}(\.\d{2})?$"
Here's how I think it should work (but clearly
I'm wrong, because it does not actually work):
^\$\£? Require zero or one instance of $ or £ at the start of the string.
d{0,10} Next, require between zero and ten alpha characters.
(\.\d{2})? Optionally, two characters can
follow. They must be preceded by a decimal point.
Examples of acceptable input should be:
$12.42
$12
£12.42
$12,482.96 (now I think about it, I have not catered for this in my regexp)
And unacceptable input would be:
$12b.42
blah
$blah
etc
Here is my Python script:
#
import re
def is_currency(str):
rex = "^\$\£?\d{0,10}(\.\d{2})?$"
if re.match(rex, str):
return 1
else:
return 0
def test_match(str):
if is_currency (str):
print str + " is a match"
else:
print str + " is not a match"
# All should match except the last two
test_match("$12.47")
test_match("12.47")
test_match("£12.47")
test_match("£12")
test_match("$12")
test_match("$12588.47")
test_match("$12,588.47")
test_match("£12588.47")
test_match("12588.47")
test_match("£12588")
test_match("$12588")
test_match("blah")
test_match("$12b.56")
AND HERE IS THE OUTPUT FROM THE ABOVE SCRIPT:
$12.47 is a match
12.47 is not a match
£12.47 is not a match
£12 is not a match
$12 is a match
$12588.47 is a match
$12,588.47 is not a match
£12588.47 is not a match
12588.47 is not a match
£12588 is not a match
$12588 is a match
blah is not a match
$12b.56 is not a match
Many thanks in advance. Regular expressions are not my strong suit :)
J-C
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