
    Write a function to extract only the primary academic performance indicators from a student's encoded performance string, where primary indicators are stored at even indices (0-based) in the string. The function should discard all supplementary metrics stored at odd indices, returning only the core performance data needed for analysis.
    

    
def odd_values_string(str):
    """
    Write a function to extract only the primary academic performance indicators from a student's encoded performance string, where primary indicators are stored at even indices (0-based) in the string. The function should discard all supplementary metrics stored at odd indices, returning only the core performance data needed for analysis.
    

    """
def odd_values_string(str):
    """
    Write a function to extract only the primary academic performance indicators from a student's encoded performance string, where primary indicators are stored at even indices (0-based) in the string. The function should discard all supplementary metrics stored at odd indices, returning only the core performance data needed for analysis.
    

    """
    result = ''
    for i in range(len(str)):
        if i % 2 == 0:
            result = result + str[i]
    return result