import re
strings = [
	['28k ring to be worn', '90w20h','96k watch', 'final price'],
    ['28k ring to be worn', '90.8w20.6h','96k watch', 'final price'],
    ['28k ring to be worn','90.8  w  20.6h','96k watch', 'final price'],
    ['28k ring to be worn', '90.8  20.6h','96k watch', 'final price']
]
for text in strings:
	matches = re.findall(r'\d+(?:\.\d+)?k|(\d+(?:\.\d+)?)', ' '.join(text), re.I)
	print( [m for m in matches if m!=''] )