def test_string_content(string):
    """
    Detects if string is integer, float or string.

    Parameters
    ----------
    string : string
        An input string to be tested.

    Returns
    -------
    string
        A string with value 'int' if input is an integer,
        'float' if the input is a float and 'string' if it
        is just a regular string.

    """
    try:
        float(string)
        return 'int' if string.count('.'
            ) == 0 and 'e' not in string and 'E' not in string else 'float'
    except ValueError:
        return 'string'
