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RSS订阅原创 python pandas行操作 10
import pandas as pd page_001 = pd.read_excel('Students.xlsx',sheet_name = 'Page_001')page_002 = pd.read_excel('Students.xlsx',sheet_name = 'Page_002')students = page_001.append(page_002)reset_index(drop = True)# 不管原来indexstu = pd.Series({'ID':41,'Name
2021-05-13 23:21:27
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原创 python pandas透视表pivot table 09
方法一：import pandas as pdpd.options.display.max_columns = 999orders = pd.read_excel('Orders.xlsx')orders['Year'] = pd.DatetimeIndex(orders['Date']).year pt1 = orders.pivot_table(index = 'Category',columns='Year',values= 'Total',aggfunc = np.sum)方法二：
2021-05-13 22:43:17
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原创 python pandas 一列拆分08
把一列拆分成两列例如name拆分成first name+last nameimport pandas as pdemployees = pd.read_excel('employee.xlsx',index_col = 'ID')df = employees['Full Name'].str.split(n=3,expand = True)# 默认空格切割 n:最多保留个数employees['Fiest Name'] = df[0].str.upper()# 全大写employees
2021-05-13 22:21:25
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原创 python pandas 数据校验07
import pandas as pd def score_validation(row): try: assert 0<=row.Score<=100 except: print(f'#{row.ID}student{row.Name}has an invalid score {row.Score}.')students = pd.read_excel('bookds.xlsx')students.apply(score_validation,axis=1) import
2021-05-13 18:20:43
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原创 python pandas多表联合VLOOKUP 06
excel=if NA(vlookup(),0)----当NA的时候为0方法一import pandas as pdstudents = pd.read_excel('bookds.xlsx', sheet_name='Students',index_col ='ID')scores = pd.read_excel('bookds.xlsx', sheet_name='Scores',index_col ='ID')# 一旦设为index就从普通列中消失了table = student
2021-05-13 18:09:29
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原创 python pandas 可视化图表 05
import pandas as pdimport matplotlib.pyplot as pltbooks = pd.read_excel('bookds.xlsx', index_col='ID')books['Price'] = books['ListPrice'] * books['Discount']课时09
2021-05-13 17:32:12
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原创 python pandas 筛选04
方法优化import pandas as pddef age_18_to_30(a): return 18<=a<30def level_a(s): return 85<=s<=100students = pd.read_excel('students.xlsx', index_col='ID')students = students.loc[students['Age'].apply[age_18_to_30]].loc[students['Score'].appl
2021-05-13 17:29:47
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原创 python pandas 函数运用 筛选 03
公式计算*方法一import pandas as pdbooks = pd.read_excel('bookds.xlsx', index_col='ID')books['Price'] = books['ListPrice'] * books['Discount']# 操作符的重载方法二：用for loopimport pandas as pdbooks = pd.read_excel('bookds.xlsx', index_col='ID')for i in books.inde
2021-05-13 17:19:30
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原创 python pandas series 02
序列series 理解import pandas as pd# dict 很像 key value pair d =（'x':100）d =（'x':100）s1 = pd.Series(d)# index是 x value 是100import pandas as pdL1 = [100,200,300]L2 = ['x','y','z']s1 = pd.Series(L1， index = L2)# 或者直接值放进去 s1 = pd.Series([100,200,300]， in
2021-05-13 16:34:04
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原创 python pandas 文件读取 01
创建文件df = pd.DataFrame()# 一个 worksheetdf = pd.DataFrame({'ID':[1,2,3]})# 加数据 此时会多出一列012···作为索引# 若想让ID作为索引df = df.set_index('ID')读文件import pandas as pdall_player = pd.read_excel('allplayer.xls')games = pd.read_excel('allplayer.xlsx')res = pd.merg
2021-05-13 14:55:21
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原创 SQL 笔记1
IN 和 EXIST 区别SELECT count(*) FROM Parts p1WHERE NOT EXISTS (SELECT needsPart FROM Parts p2 WHERE p1.partNumber = p2.needsPart)SELECT count(*) FROM Parts p1WHERE p1.partNumber NOT IN (SELECT needsPart FROM Parts p2 WHERE p1.partNumber = p2.needsPar
2021-03-26 20:08:41
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原创 报错 Incompatible pointer types initializing ‘int *‘ with an expression of type ‘float *‘
#报错 Incompatible pointer types initializing ‘int *’ with an expression of type ‘float *’ float f; scanf("%f", &f); int *int_p = (int*)&f;注意加上 (int*)
2020-11-20 17:39:13
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