pandas - DataFrame 合并行、合并列

pandas - DataFrame

1、 合并列

def merge_cols():
    """
    合并列
    :return:
    """
    data_1 = [
        ["a", 11],
        ["b", 12],
        ["c", 13],
        ["d", 14],
        ["e", 15]
    ]
    data_2 = [
        ["a", 'col-31', 'col-41'],
        ["b", 'col-32', 'col-42'],
        ["c", 'col-33', 'col-43'],
        ["d", 'col-34', 'col-44'],
        ["e", 'col-35', 'col-45']
    ]
    columns_1 = ['col-1', 'col-2']
    columns_2 = ['col-1', 'col-3', 'col-4']
    index = ['idx-1', 'idx-2', 'idx-3', 'idx-4', 'idx-5']

    df_1 = pd.DataFrame(data=data_1, index=index, columns=columns_1)
    df_2 = pd.DataFrame(data=data_2, index=index, columns=columns_2)

    # 合并
    merge_1 = pd.merge(df_1, df_2, on="col-1")
    merge_2 = pd.merge(df_1, df_2)
    print(merge_1)
    print(merge_2)

merge_1、merge_2 返回结果：

	  col-1  col-2   col-3   col-4
	0     a     11  col-31  col-41
	1     b     12  col-32  col-42
	2     c     13  col-33  col-43
	3     d     14  col-34  col-44
	4     e     15  col-35  col-45

2、 合并行

def merge_rows():
    """
    合并行
    :return:
    """
    data_1 = [
        [11, 12, 13, 14],
        [21, 22, 23, 24],
        [31, 32, 33, 34],
        [41, 42, 43, 44],
        [51, 52, 53, 54]
    ]
    data_2 = [
        [141, 142, 143, 144],
        [151, 152, 153, 154]
    ]
    columns = ['col-1', 'col-2', 'col-3', 'col-4']
    index = ['idx-1', 'idx-2', 'idx-3', 'idx-4', 'idx-5']

    df_1 = pd.DataFrame(data=data_1, index=index, columns=columns)
    df_2 = pd.DataFrame(data=data_2, index=["idx-101", "idx-102"], columns=columns)

    # 插入单行
    df = df_1.append(df_2)
    print(df)

df 返回结果：

	         col-1  col-2  col-3  col-4
	idx-1       11     12     13     14
	idx-2       21     22     23     24
	idx-3       31     32     33     34
	idx-4       41     42     43     44
	idx-5       51     52     53     54
	idx-101    141    142    143    144
	idx-102    151    152    153    154