pattern match for integer using regex in python pandas series code example

Example 1: pandas show column with regular expression

S=pd.Series(['Finland','Colombia','Florida','Japan','Puerto Rico','Russia','france'])
S.str.contains('^F.*')

Example 2: pandas show column with regular expression

# Get countries starting with letter P
S=pd.Series(['Finland','Colombia','Florida','Japan','Puerto Rico','Russia','france'])
S[S.str.match(r'(^P.*)')==True]