6
從一般意義上說,我期望解決的問題是將多級索引的一個組件更改爲列。也就是說,我有一個Series
,它包含一個多級索引,我希望索引的最低級別更改爲dataframe
中的列。這裏是實際例子問題我想解決,MultiLevel index to columns:將value_counts獲取爲pandas中的列
在這裏我們可以生成一些樣本數據:
foo_choices = ["saul", "walter", "jessee"]
bar_choices = ["alpha", "beta", "foxtrot", "gamma", "hotel", "yankee"]
df = DataFrame([{"foo":random.choice(foo_choices),
"bar":random.choice(bar_choices)} for _ in range(20)])
df.head()
這給了我們,
bar foo
0 beta jessee
1 gamma jessee
2 hotel saul
3 yankee walter
4 yankee jessee
...
現在,我可以GROUPBY bar
並獲得foo
字段的值value_counts,
dfgb = df.groupby('foo')
dfgb['bar'].value_counts()
並輸出,
foo
jessee hotel 4
gamma 2
yankee 1
saul foxtrot 3
hotel 2
gamma 1
alpha 1
walter hotel 2
gamma 2
foxtrot 1
beta 1
但我想是這樣,
hotel beta foxtrot alpha gamma yankee
foo
jessee 1 1 5 4 1 1
saul 0 3 0 0 1 0
walter 1 0 0 1 1 0
我的解決辦法是寫以下位:
for v in df['bar'].unique():
if v is np.nan: continue
df[v] = np.nan
df.ix[df['bar'] == v, v] = 1
dfgb = df.groupby('foo')
dfgb.count()[df['bar'].unique()]
THANK YOU! 'unpack'在哪裏隱藏? – milkypostman 2012-08-15 15:47:28