Regular expression to find a sequence of numbers before multiple patterns, into a new column (Python, Pandas)

You can use str.extract:

cars['HP'] = cars['Engine Information'].str.extract(r'(\d+)\s*hp\b', flags=re.I)

Details

• (\d+)\s*hp\b - matches and captures into Group 1 one or more digits, then just matches 0 or more whitespaces (\s*) and hp (in a case insensitive way due to flags=re.I) as a whole word (since \b marks a word boundary)
• str.extract only returns the captured value if there is a capturing group in the pattern, so the hp and whitespaces are not part of the result.

Python demo results:

>>> cars
                               Engine Information   HP
0         Honda 2.4L 4 cylinder 190 hp 162 ft-lbs  190
1  Aston Martin 4.7L 8 cylinder 420 hp 346 ft-lbs  420
2          Dodge 5.7L 8 Cylinder 390hp 407 ft-lbs  390
3          MINI 1.6L 4 Cylinder 118 hp 114 ft-lbs  118
4       Ford 5.0L 8 Cylinder 360hp 380 ft-lbs FFV  360
5           GMC 6.0L 8 Cylinder 352 hp 382 ft-lbs  352