import re


def regex_capture(pattern, list_of_strings, take_index=0):
    """Apply regex `pattern` to each string and return a captured group.
    
    pattern : string, regex pattern
    list_of_strings : list of strings to apply the pattern to
        Strings that do not match the pattern are ignored.
    take_index : The index of the captured group to return
    
    Returns: a list of strings. Each element is the captured group from
        one of the input strings.
    """
    res_l = []
    for s in list_of_strings:
        m = re.match(pattern, s)
        
        # Append the capture, if any
        if m is not None:
            res_l.append(m.groups()[take_index])
    
    return res_l