[英]Python pandas count occurrences in each column
I am new to pandas. 我是熊猫新手。 Can someone help me in calculating frequencies of values for each columns.
有人可以帮助我计算每一列的值频率吗?
Dataframe: 数据帧:
id|flag1|flag2|flag3|
---------------------
1 | 1 | 2 | 1 |
2 | 3 | 1 | 1 |
3 | 3 | 4 | 4 |
4 | 4 | 1 | 4 |
5 | 2 | 3 | 2 |
I want something like 我想要类似的东西
id|flag1|flag2|flag3|
---------------------
1 | 1 | 2 | 2 |
2 | 1 | 1 | 1 |
3 | 2 | 1 | 0 |
4 | 1 | 1 | 2 |
Explanation - id 1 has 1 value in flag1, 2 values in flag2 and 2 values in flag3. 说明-id 1在flag1中具有1个值,在flag2中具有2个值,在flag3中具有2个值。
First filter only flag
columns by filter
or removing id
column and then apply
function value_counts
, last replace NaN
s to 0
and cast to int
s: 首先通过
filter
或删除id
列仅过滤flag
列,然后apply
函数value_counts
,最后将NaN
替换为0
并强制转换为int
:
df = df.filter(like='flag').apply(lambda x: x.value_counts()).fillna(0).astype(int)
print (df)
flag1 flag2 flag3
1 1 2 2
2 1 1 1
3 2 1 0
4 1 1 2
Or: 要么:
df = df.drop('id', 1).apply(lambda x: x.value_counts()).fillna(0).astype(int)
print (df)
flag1 flag2 flag3
1 1 2 2
2 1 1 1
3 2 1 0
4 1 1 2
Thank you, Bharath for suggestion: 谢谢巴拉斯的建议:
df = df.filter(like='flag').apply(pd.Series.value_counts()).fillna(0).astype(int)
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