【数据分析可视化】通过apply进行数据预处理

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import numpy as np
import pandas as pd
from pandas import Series, DataFrame

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# 读取apply_demo.csv数据
link_csv = '/Users/bennyrhys/Desktop/数据分析可视化-数据集/homework/apply_demo.csv'
df = pd.read_csv(link_csv).head()
df

	time	data
0	1473411962	Symbol: APPL Seqno: 0 Price: 1623
1	1473411962	Symbol: APPL Seqno: 0 Price: 1623
2	1473411963	Symbol: APPL Seqno: 0 Price: 1623
3	1473411963	Symbol: APPL Seqno: 0 Price: 1623
4	1473411963	Symbol: APPL Seqno: 1 Price: 1649

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df.size

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# 新加一列Series
s1 = Series(['a']*10)
s1

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0    a
1    a
2    a
3    a
4    a
5    a
6    a
7    a
8    a
9    a
dtype: object

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df['A'] = s1
df.head()

	time	data	A
0	1473411962	Symbol: APPL Seqno: 0 Price: 1623	a
1	1473411962	Symbol: APPL Seqno: 0 Price: 1623	a
2	1473411963	Symbol: APPL Seqno: 0 Price: 1623	a
3	1473411963	Symbol: APPL Seqno: 0 Price: 1623	a
4	1473411963	Symbol: APPL Seqno: 1 Price: 1649	a

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# 将A列小写全变为大写（函数.apply(str.upper)）
df['A'] = df['A'].apply(str.upper)
df

	time	data	A
0	1473411962	Symbol: APPL Seqno: 0 Price: 1623	A
1	1473411962	Symbol: APPL Seqno: 0 Price: 1623	A
2	1473411963	Symbol: APPL Seqno: 0 Price: 1623	A
3	1473411963	Symbol: APPL Seqno: 0 Price: 1623	A
4	1473411963	Symbol: APPL Seqno: 1 Price: 1649	A

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# 切分去除data数据
df['data'][0]

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' Symbol: APPL Seqno: 0 Price: 1623'

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# 去除头尾strip，且空格分割split
l1 = df['data'][0].strip().split(' ')
l1

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['Symbol:', 'APPL', 'Seqno:', '0', 'Price:', '1623']

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# 想要的是字典值
l1[1],l1[3],l1[5]

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('APPL', '0', '1623')

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# 写分割返回函数
def foo(line):
    items = line.strip().split(' ')
    return Series([items[1],items[3],items[5]])

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# 分割完生成新的数框
df_tmp = df['data'].apply(foo)
df_tmp

	0	1	2
0	APPL	0	1623
1	APPL	0	1623
2	APPL	0	1623
3	APPL	0	1623
4	APPL	1	1649

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# 新的数框 重命名
df_tmp = df_tmp.rename(columns={0:'Symbol',1:'Seqno',2:'Price'})
df_tmp

	Symbol	Seqno	Price
0	APPL	0	1623
1	APPL	0	1623
2	APPL	0	1623
3	APPL	0	1623
4	APPL	1	1649

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df

	time	data	A
0	1473411962	Symbol: APPL Seqno: 0 Price: 1623	A
1	1473411962	Symbol: APPL Seqno: 0 Price: 1623	A
2	1473411963	Symbol: APPL Seqno: 0 Price: 1623	A
3	1473411963	Symbol: APPL Seqno: 0 Price: 1623	A
4	1473411963	Symbol: APPL Seqno: 1 Price: 1649	A

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# 新旧两个数框 结合
df_new = df.combine_first(df_tmp)
df_new

	A	Price	Seqno	Symbol	data	time
0	A	1623.0	0.0	APPL	Symbol: APPL Seqno: 0 Price: 1623	1473411962
1	A	1623.0	0.0	APPL	Symbol: APPL Seqno: 0 Price: 1623	1473411962
2	A	1623.0	0.0	APPL	Symbol: APPL Seqno: 0 Price: 1623	1473411963
3	A	1623.0	0.0	APPL	Symbol: APPL Seqno: 0 Price: 1623	1473411963
4	A	1649.0	1.0	APPL	Symbol: APPL Seqno: 1 Price: 1649	1473411963

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# 去掉多余已经处理的data
del df_new['data']
del df_new['A']
df_new

	Price	Seqno	Symbol	time
0	1623.0	0.0	APPL	1473411962
1	1623.0	0.0	APPL	1473411962
2	1623.0	0.0	APPL	1473411963
3	1623.0	0.0	APPL	1473411963
4	1649.0	1.0	APPL	1473411963

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# 转存到外部继续用
df_new.to_csv('/Users/bennyrhys/Desktop/数据分析可视化-数据集/homework/demo_duplicate.csv')

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!ls /Users/bennyrhys/Desktop/数据分析可视化-数据集/homework

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AMZN.csv           apply_demo.csv     iris.csv           top5.csv
BABA.csv           city_weather.csv   movie_metadata.csv train.csv
Pokemon.csv        demo_duplicate.csv sales-funnel.xlsx  usa_flights.csv

data time

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