Python 按字母顺序排列数据框
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Python order dataframe alphabetically
提问by Sheron
I would like to reorder dataframe by student name. Does anybody have some suggestions?
我想按学生姓名重新排序数据框。有人有什么建议吗？
df = pd.DataFrame({
'student': [
'monica', 'nathalia', 'anastasia', 'marina', 'ema'
],
'grade' : ['excellent', 'excellent', 'good', 'very good', 'good'
]
})
print (df)
student grade
0 monica excellent
1 nathalia excellent
2 anastasia good
3 marina very good
4 ema good
回答by sgrg
Pre pandas 0.17:
熊猫 0.17 前：
# Sort by ascending student name
df.sort('student')
# reverse ascending
df.sort('student', ascending=False)
Pandas 0.17+ (as mentioned in the other answers):
Pandas 0.17+（如其他答案中所述）：
# ascending
df.sort_values('student')
# reverse ascending
df.sort_values('student', ascending=False)
回答by James
You can sort a dataframe using the sort_valuesmethod.
您可以使用该sort_values方法对数据框进行排序。
df.sort_values('student')
回答by qbzenker
try
尝试
df.sort_values(by='student')
or, if you want Z first:
或者，如果你先想要 Z：
df.sort_values(by='student', ascending=False)
回答by piRSquared
pd.DataFrame.sort_valuesis the obvious pandaschoice
pd.DataFrame.sort_values是显而易见的pandas选择
However, you can use numpyand reconstruct. This will give you a modest performance boost.
但是，您可以使用numpy和重建。这将为您带来适度的性能提升。
a = df.student.values.astype(str).argsort()
pd.DataFrame(df.values[a], df.index[a], df.columns)
grade student
2 good anastasia
4 good ema
3 very good marina
0 excellent monica
1 excellent nathalia
testing over small data
小数据测试
testing over larger data
测试更大的数据
回答by everestial007
pandas 0.19.2
熊猫 0.19.2
df.sort_values(by=['contig', 'pos'], ascending=True)
# where contig and pos are the column names. So, you may change for yours.
Note:Use of inplaceis very essential if you want to update the same dataframe. Most of the people run into confusion about when to use/not-use inplace.
注意：inplace如果要更新相同的数据框，则使用非常重要。大多数人对何时使用/不使用就地感到困惑。
If you want to make a new-dataframe.
如果你想制作一个新的数据框。
df_sorted = df.sort_values(by=['contig', 'pos'], inplace=False, ascending=True)
