CSV模块

Posted 2020-10-11 韩乾

 

有如下文本

Symbol,Price,Date,Time,Change,Volume
"AA",39.48,"6/11/2007","9:36am",-0.18,181800
"AIG",71.38,"6/11/2007","9:36am",-0.15,195500
"AXP",62.58,"6/11/2007","9:36am",-0.46,935000
"BA",98.31,"6/11/2007","9:36am",+0.12,104800
"C",53.08,"6/11/2007","9:36am",-0.25,360900
"CAT",78.29,"6/11/2007","9:36am",-0.23,225400

 

使用字符串下标取某一列

import csv
from collections import namedtuple
with open(‘l.csv‘,‘r‘) as f:
    fcsv = csv.reader(f,delimiter=‘,‘)
    header = next(f)
    Row = namedtuple(‘Row‘, header)
    for i in fcsv:
        row = Row(*i) 
              
row.Date 输出：
6/11/2007
6/11/2007
6/11/2007
6/11/2007
6/11/2007
6/11/2007
     
row 输出：
Row(Symbol=‘AA‘, Price=‘39.48‘, Date=‘6/11/2007‘, Time=‘9:36am‘, Change=‘-0.18‘, Volume=‘181800‘)
Row(Symbol=‘AIG‘, Price=‘71.38‘, Date=‘6/11/2007‘, Time=‘9:36am‘, Change=‘-0.15‘, Volume=‘195500‘)
Row(Symbol=‘AXP‘, Price=‘62.58‘, Date=‘6/11/2007‘, Time=‘9:36am‘, Change=‘-0.46‘, Volume=‘935000‘)
Row(Symbol=‘BA‘, Price=‘98.31‘, Date=‘6/11/2007‘, Time=‘9:36am‘, Change=‘+0.12‘, Volume=‘104800‘)
Row(Symbol=‘C‘, Price=‘53.08‘, Date=‘6/11/2007‘, Time=‘9:36am‘, Change=‘-0.25‘, Volume=‘360900‘)
Row(Symbol=‘CAT‘, Price=‘78.29‘, Date=‘6/11/2007‘, Time=‘9:36am‘, Change=‘-0.23‘, Volume=‘225400‘)

 

 

 

使用字典取某一列

import csv
with open(‘l.csv‘,‘r‘) as f:
    fcsv = csv.DictReader(f)
    for i in fcsv:
        print i[‘Symbol‘]
输出：
{‘Symbol‘: ‘AA‘, ‘Volume‘: ‘181800‘, ‘Time‘: ‘9:36am‘, ‘Date‘: ‘6/11/2007‘, ‘Price‘: ‘39.48‘, ‘Change‘: ‘-0.18‘}
{‘Symbol‘: ‘AIG‘, ‘Volume‘: ‘195500‘, ‘Time‘: ‘9:36am‘, ‘Date‘: ‘6/11/2007‘, ‘Price‘: ‘71.38‘, ‘Change‘: ‘-0.15‘}
{‘Symbol‘: ‘AXP‘, ‘Volume‘: ‘935000‘, ‘Time‘: ‘9:36am‘, ‘Date‘: ‘6/11/2007‘, ‘Price‘: ‘62.58‘, ‘Change‘: ‘-0.46‘}
{‘Symbol‘: ‘BA‘, ‘Volume‘: ‘104800‘, ‘Time‘: ‘9:36am‘, ‘Date‘: ‘6/11/2007‘, ‘Price‘: ‘98.31‘, ‘Change‘: ‘+0.12‘}
{‘Symbol‘: ‘C‘, ‘Volume‘: ‘360900‘, ‘Time‘: ‘9:36am‘, ‘Date‘: ‘6/11/2007‘, ‘Price‘: ‘53.08‘, ‘Change‘: ‘-0.25‘}
{‘Symbol‘: ‘CAT‘, ‘Volume‘: ‘225400‘, ‘Time‘: ‘9:36am‘, ‘Date‘: ‘6/11/2007‘, ‘Price‘: ‘78.29‘, ‘Change‘: ‘-0.23‘}

 

 

 

写CSV文件

import csv
headers = [‘aa‘,‘bb‘,‘cc‘,‘dd‘]
rows = [{‘aa‘:‘111‘,‘bb‘:‘222‘,‘cc‘:‘333‘,‘dd‘:‘444‘},
        {‘aa‘:‘1111‘,‘bb‘:‘2222‘,‘cc‘:‘3333‘,‘dd‘:‘4444‘}
        ]
with open(‘tt.csv‘,‘w‘) as f:                               
    f_csv = csv.DictWriter(f, headers)
    f_csv.writeheader()
    f_csv.writerows(rows)
cat tt.csv
aa,bb,cc,dd
111,222,333,444
1111,2222,3333,4444