What is the python deduplication function?

Data deduplication can use two methods: duplicated() and drop_duplicates().

DataFrame.duplicated(subset=None, keep='first') returns a boolean Series representing duplicate rows

Parameters:

subset: column label or label sequence, optional

Only certain columns are considered for identifying duplicates, by default all columns are used

keep: {'first', 'last', False}, default 'first'

first: Mark duplicates, True except for the first occurrence.

last: Marks duplicates, True except for the last occurrence.

Error: Mark all duplicates as True.

Related recommendations: "Python Basic Tutorial"

import numpy as np
import pandas as pd
from pandas import Series, DataFrame
df = pd.read_csv('./demo_duplicate.csv')
print(df)
print(df['Seqno'].unique()) # [0. 1.]
# 使用duplicated 查看重复值
# 参数 keep 可以标记重复值 {'first'，'last'，False}
print(df['Seqno'].duplicated())
'''
0    False
1     True
2     True
3     True
4    False
Name: Seqno, dtype: bool
'''
# 删除 series 重复数据
print(df['Seqno'].drop_duplicates())
'''
0    0.0
4    1.0
Name: Seqno, dtype: float64
'''
# 删除 dataframe 重复数据
print(df.drop_duplicates(['Seqno'])) # 按照 Seqno 来去重
'''
   Price     Seqno   Symbol   time
0  1623.0    0.0   APPL  1473411962
4  1649.0    1.0   APPL  1473411963
'''
# drop_dujplicates() 第二个参数 keep 包含的值 有： first、last、False
print(df.drop_duplicates(['Seqno'], keep='last')) # 保存最后一个
'''
   Price     Seqno   Symbol   time
3  1623.0    0.0   APPL  1473411963
4  1649.0    1.0   APPL  1473411963
'''

The above is the detailed content of What is the python deduplication function?. For more information, please follow other related articles on the PHP Chinese website!