计算总行数，不包括子行

def count_lines(file_content):
    lines = file_content.split('\n')
    total_lines = 0
    for line in lines:
        if not is_subline(line):
            total_lines += 1
    return total_lines

def is_subline(line):
    # 判断是否为子行的逻辑，根据实际需求进行实现
    # 这里只是一个示例，可以根据具体情况进行修改
    if line.startswith('\t') or line.startswith('    '):
        return True
    return False

# 示例用法
file_content = """
This is line 1.
    This is a subline.
This is line 2.
This is line 3.
    This is another subline.
This is line 4.
"""
total_lines = count_lines(file_content)
print("Total lines (excluding sublines):", total_lines)