双层饼图（two layer pie plot）

简介
在常规饼图外，再嵌套一层饼图，双层饼图
数据说明
数据包含3行，第1列是说明，第2行是外圈数值，第3行是内圈数值。
论文例子
Intertumoral Genetic Heterogeneity Generates Distinct Tumor Microenvironments in a Novel Murine Synchronous Melanoma Model. Fig3a
论文写作
Nested pie charts demonstrating distributions of various CD45+ immune cell subsets in synchronous ER (ER + Y) and Y (ER + Y) tumors with Y tumor as the inside pie and ER tumor the outside pie.

输入	items Ann Bob Carl David day1 1 2 3 4 day2 2 5 4 7
输出

如何引用？

建议直接写网址。助力10000+篇（google学术），8500+篇（知网）论文
正式引用：Tang D, Chen M, Huang X, Zhang G, Zeng L, Zhang G, Wu S, Wang Y. SRplot: A free online platform for data visualization and graphing. PLoS One. 2023 Nov 9;18(11):e0294236. doi: 10.1371/journal.pone.0294236. PMID: 37943830.
方法章节：Heatmap was plotted by https://www.bioinformatics.com.cn (last accessed on May 4, 2026), an online platform for data analysis and visualization.
致谢章节：We thank Mingjie Chen (Shanghai NewCore Biotechnology Co., Ltd.) for providing data analysis and visualization support.