re = /(?<=:|^)(?!.*:)(?=.*([Ee]ur|EUR)).*/m
str = '[
"ERDF : EUR 2.7 million",
"ERDF : EUR 961 000",
"ERDF: 7 305 000 DKR (+/- EUR 974 000) ",
FEOGA: 40 826 EUR",
"49 % of eligible costs",
"ERDF contribution: 64%",
"FEDER (Objectif 5b 1994-1996) 60 979 euros (400 000 FRF)",
"FEDER, Objectif 2, 1994 - 1999: 1 116 000 EUR",
"EUR 8.000.000",
"EUR 7.200.000",
"EUR 4.200.000",
"EUR 0.2 million",
"EUR 0.6 million",
"FEDER: 830 842 euros (5 450 000 FRF)",
"EUR 7,220,000,000",
"DKR 1 220 000 + DKR 1 380 000 ",
"GBP 150 000"
]'
subst = ''
result = str.gsub(re, subst)
# Print the result of the substitution
puts result
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Ruby, please visit: http://ruby-doc.org/core-2.2.0/Regexp.html