Python 将列表写入 csv

Question

每次循环运行时，如何将 print 语句中的结果写入 csv 文件，并将结果添加到下一行。结果包含一个列表。

def func_high(i):
    swing_low = data_file.iloc[i].Low    
    date =  data_file.iloc[i].Date

    while i < len(data_file):
        i = i + 1

        try :
           swing_high = data_file.iloc[i].High
           if (swing_high < data_file.iloc[i + 1].High) and (data_file.iloc[i + 1].High > data_file.iloc[i + 2].High):
               date_diff = data_file.iloc[i + 1].Date - date
               price_diff = data_file.iloc[i + 1].High - swing_low
               **print (price_diff/date_diff.days, date, swing_low , data_file.iloc[i + 1].Date, data_file.iloc[i + 1].High, date_diff)**

    except IndexError:
        pass
    continue

Answer 1

您可以将 print 更改为 yield，并使用 csv.writer (我对您的函数进行了一些其他编辑，以便我可以更容易遵循逻辑)。

import csv
i = 0

def func_high(i):
    swing_low = data_file.iloc[i].Low    
    date =  data_file.iloc[i].Date
    while i < (len(data_file) - 3):
        i += 1

        swing_high = data_file.iloc[i].High
        curr_date = data_file.iloc[i + 1].Date
        curr_high = data_file.iloc[i + 1].High
        next_high = data_file.iloc[i + 2].High

        if (swing_high < curr_high) and (curr_high > next_high):
            date_diff =  curr_date - date
            price_diff = curr_high - swing_low
            avg_change = price_diff/date_diff.days
            yield [avg_change, date, swing_low, curr_date, curr_high, date_diff]


with open('my_csv.csv', 'w') as out_f:
    writer = csv.writer(out_f, lineterminator='\n') 
    writer.writerows(func_high(i))

如果您想走 pandas 路线，您可以使用上面的生成器执行以下操作。

pd.DataFrame(list(func_high(i)).to_csv('my_csv.csv',index=False, header=False)