I am trying to sort each row of a DataFrame element wise.
Input:
A B C
0 10 5 6
1 3 6 5
2 1 2 3
Output:
A B C
0 10 6 5
1 6 5 3
2 3 2 1
It feels this should be easy but I've been failing for while... Very much a beginner in Python.
Use np.sort with swap ordering by indexing:
df1 = pd.DataFrame(np.sort(df.to_numpy(), axis=1)[:, ::-1],
index=df.index,
columns=df.columns)
print (df1)
A B C
0 10 6 5
1 6 5 3
2 3 2 1
Pandas solution, slowier, is apply sorting for each row separately, convert to array and then to Series:
f = lambda x: pd.Series(x.sort_values(ascending=False).to_numpy(), index=df.columns)
df1 = df.apply(f, axis=1)
print (df1)
A B C
0 10 6 5
1 6 5 3
2 3 2 1
If possible missing values for me working:
print (df)
A B C
0 10.0 6.0 5.0
1 5.0 3.0 NaN
2 2.0 1.0 NaN
df1 = pd.DataFrame(np.sort(df.to_numpy(), axis=1)[:, ::-1],
index=df.index,
columns=df.columns)
print (df1)
A B C
0 10.0 6.0 5.0
1 NaN 5.0 3.0
2 NaN 2.0 1.0
In pandas is possible use na_position parameter for specify order of them:
f = lambda x: pd.Series(x.sort_values(ascending=False, na_position='first').to_numpy(),
index=df.columns)
df1 = df.apply(f, axis=1)
print (df1)
A B C
0 10.0 6.0 5.0
1 NaN 5.0 3.0
2 NaN 2.0 1.0
f = lambda x: pd.Series(x.sort_values(ascending=False, na_position='last').to_numpy(),
index=df.columns)
df1 = df.apply(f, axis=1)
print (df1)
A B C
0 10.0 6.0 5.0
1 5.0 3.0 NaN
2 2.0 1.0 NaN
.to_numpy() ?stocks.sort, need np.sortNaNs