Pandas 将两列合并到另一列 Dataframe

Question

我想基于 Squad 列df1将两列合并到另一个 dataframe

    Squad
0   Arsenal
1   Aston Villa
2   Bournemouth
3   Brighton
4   Burnley
5   Chelsea
6   Crystal Palace
7   Everton
8   Leicester City
9   Liverpool
10  Manchester City
11  Manchester Utd
12  Newcastle Utd
13  Norwich City
14  Sheffield Utd
15  Southampton
16  Tottenham
17  Watford
18  West Ham
19  Wolves

df2

    Rk  Squad   MP  W   D   L   GF  GA  GD  Pts ... L   GF  GA  GD  Pts Pts/G   xG  xGA xGD xGD/90
0   1   Liverpool   19  18  1   0   52  16  36  55  ... 3   33  17  16  44  2.32    31.2    21.6    9.5 0.50
1   2   Manchester City 19  15  2   2   57  13  44  47  ... 7   45  22  23  34  1.79    45.5    19.5    26.0    1.37
2   3   Manchester Utd  19  10  7   2   40  17  23  37  ... 6   26  19  7   29  1.53    28.4    21.1    7.4 0.39
3   4   Chelsea 19  11  3   5   30  16  14  36  ... 7   39  38  1   30  1.58    29.2    27.2    2.0 0.10
4   5   Leicester City  19  11  4   4   35  17  18  37  ... 8   32  24  8   25  1.32    31.0    22.7    8.3 0.44
5   6   Tottenham   19  12  3   4   36  17  19  39  ... 7   25  30  -5  20  1.05    21.6    28.7    -7.1    -0.37
6   7   Wolves  19  8   7   4   27  19  8   31  ... 5   24  21  3   28  1.47    21.2    18.3    2.9 0.15
7   8   Arsenal 19  10  6   3   36  24  12  36  ... 7   20  24  -4  20  1.05    22.0    25.8    -3.8    -0.20
8   9   Sheffield Utd   19  10  3   6   24  15  9   33  ... 6   15  24  -9  21  1.11    15.3    28.2    -12.9   -0.68
9   10  Burnley 19  8   4   7   24  23  1   28  ... 7   19  27  -8  26  1.37    16.6    27.1    -10.4   -0.55
10  11  Southampton 19  6   3   10  21  35  -14 21  ... 6   30  25  5   31  1.63    30.8    24.9    5.9 0.31
11  12  Everton 19  8   7   4   24  21  3   31  ... 11  20  35  -15 18  0.95    21.8    24.9    -3.1    -0.16
12  13  Newcastle Utd   19  6   8   5   20  21  -1  26  ... 11  18  37  -19 18  0.95    15.0    30.3    -15.3   -0.81
13  14  Crystal Palace  19  6   5   8   15  20  -5  23  ... 9   16  30  -14 20  1.05    16.4    31.6    -15.2   -0.80
14  15  Brighton    19  5   7   7   20  27  -7  22  ... 8   19  27  -8  19  1.00    20.3    28.5    -8.2    -0.43
15  16  West Ham    19  6   4   9   30  33  -3  22  ... 10  19  29  -10 17  0.89    22.5    31.9    -9.4    -0.49
16  17  Aston Villa 19  7   3   9   22  30  -8  24  ... 12  19  37  -18 11  0.58    18.5    34.5    -16.0   -0.84
17  18  Bournemouth 19  5   6   8   22  30  -8  21  ... 14  18  35  -17 13  0.68    20.4    32.3    -11.9   -0.63
18  19  Watford 19  6   6   7   22  27  -5  24  ... 13  14  37  -23 10  0.53    18.5    29.9    -11.4   -0.60
19  20  Norwich City    19  4   3   12  19  37  -18 15  ... 15  7   38  -31 6   0.32    17.7    30.2    -12.6   -0.66

我想在 df1 上创建一个新列并进行计算，即 W 列的值除以 MP 列的值。 我试图将 W 列合并到 df1 但我得到TypeError: Cannot convert bool to numpy.ndarray

df1 = pd.merge(df1, df2['Squad','W'], on='Squad',how='left')

Answer 1

尝试：

result = df1.merge(df2[['Squad','W', 'MP']], how='left')
result['new_col'] = result['W'] / result['MP']

NOTE:确保在划分之前处理NAN and 0 。