Pandas DataFrame head tail 查看前后n行数据

my_df = pd.DataFrame(data=np.arange(40).reshape(5,8),  # 5*8的矩阵
             index=list("abcde"),  # 行索引
             columns=list("ABCDEFGH"))  # 列索引
print("my_df\n",my_df)

# 前两行
print("my_df.head(2)\n",my_df.head(2))
# 后一行
print("my_df.tail(2)\n",my_df.tail(1))

my_df
     A   B   C   D   E   F   G   H
a   0   1   2   3   4   5   6   7
b   8   9  10  11  12  13  14  15
c  16  17  18  19  20  21  22  23
d  24  25  26  27  28  29  30  31
e  32  33  34  35  36  37  38  39
my_df.head(2)
    A  B   C   D   E   F   G   H
a  0  1   2   3   4   5   6   7
b  8  9  10  11  12  13  14  15
my_df.tail(2)
     A   B   C   D   E   F   G   H
e  32  33  34  35  36  37  38  39

help(my_df.head)

Help on method head in module pandas.core.generic:

head(n=5) method of pandas.core.frame.DataFrame instance
    Return the first n rows.
    
    Parameters
    ----------
    n : int, default 5
        Number of rows to select.
    
    Returns
    -------
    obj_head : type of caller
        The first n rows of the caller object.

help(my_df.tail)

Help on method tail in module pandas.core.generic:

tail(n=5) method of pandas.core.frame.DataFrame instance
    Return the last n rows.
    
    Parameters
    ----------
    n : int, default 5
        Number of rows to select.
    
    Returns
    -------
    obj_tail : type of caller
        The last n rows of the caller object.