我正在尝试将一组列表转换为数据框，但是这些列表的长度不同。如何将列表合并到一个数据框中？
str(MCP_reshape)
List of 10
$ B lineage : Factor w/ 111 levels "ACVRL1","ADAP2",..: 4 10 14 20 33 49 59 76 81
$ CD8 T cells : Factor w/ 111 levels "ACVRL1","ADAP2",..: 22
$ Cytotoxic lymphocytes : Factor w/ 111 levels "ACVRL1","ADAP2",..: 21 44 50 53 67 68 69
$ Endothelial cells : Factor w/ 111 levels "ACVRL1","ADAP2",..: 1 3 5 6 7 23 27 38 41 42 ...
$ Fibroblasts : Factor w/ 111 levels "ACVRL1","ADAP2",..: 29 30 31 32 40 54 80 98
$ Monocytic lineage : Factor w/ 111 levels "ACVRL1","ADAP2",..: 2 34 52 70 85 89 101
$ Myeloid dendritic cells: Factor w/ 111 levels "ACVRL1","ADAP2",..: 11 12 13 26 28 111
$ Neutrophils : Factor w/ 111 levels "ACVRL1","ADAP2",..: 8 24 36 37 39 48 55 60 72 96 ...
$ NK cells : Factor w/ 111 levels "ACVRL1","ADAP2",..: 9 62 63 64 65 66 78 87 92
$ T cells : Factor w/ 111 levels "ACVRL1","ADAP2",..: 15 16 17 18 19 25 35 51 58 71 ...```