如何在文件中查找矩阵的索引？

def find_matrix_index(file_path, target):
    # 读取文件
    with open(file_path, 'r') as file:
        content = file.read()

    # 解析文件内容为矩阵
    matrix = []
    rows = content.split('\n')
    for row in rows:
        elements = row.split(',')
        matrix.append(elements)

    # 查找索引
    indices = []
    for i in range(len(matrix)):
        for j in range(len(matrix[i])):
            if matrix[i][j] == target:
                indices.append((i, j))

    # 输出结果
    if indices:
        with open('result.txt', 'w') as file:
            for index in indices:
                file.write(f'({index[0]}, {index[1]})\n')
    else:
        print('未找到匹配的索引')

# 调用函数进行查找
find_matrix_index('matrix.txt', '5')