擅长:python、mysql、java
<p>对<code>pd.DataFrame.loc</code>使用布尔索引:</p>
<pre><code>m = df['colour'] == 'black'
df.loc[m, 'colour'] = df.loc[m, 'phase']
game_id move_number move colour avg_centi phase
0 03gDhPWr 1 e4 white NaN opening
1 03gDhPWr 2 d5 opening 37.0 opening
2 03gDhPWr 3 e5 white 61.0 opening
3 03gDhPWr 4 c5 opening -5.0 opening
4 03gDhPWr 5 Nf3 white 26.0 opening
110093 zzaiRa7s 36 a5+ endgame NaN endgame
110094 zzaiRa7s 37 Kxb5 white NaN endgame
110095 zzaiRa7s 38 c6+ endgame NaN endgame
110096 zzaiRa7s 39 Ka4 white NaN endgame
110097 zzaiRa7s 40 Q@b4# endgame NaN endgame
</code></pre>