Python：合并多个csv文件时需要新建一列

Question

thanks for help in advance. multi-part question

I have zip files that has multiple stock pricing info. the current format is Header row is:

ticker,date,open,high,low,close,vol

and first row example is

AAPL,201906030900,176.32,176.32,176.24,176.29,2247

---

desired format:

header

ticker,date,time,open,high,low,close,vol

---

and data

AAPL,20190603,09:00,176.32,176.32,176.24,176.29,2247

---

where the time column is added and the column is filled with the last 4 digits from the date row with a colon in the middle and those last 4 digits are removed from the date data column.

there about 400 rows of data for each stock in each file so each row would need to be converted.

i haven't been able to find an answer here or elsewhere on the web that i could understand how to accomplish what i am trying to do.

Answer 1

Try the following, using pandas :
data.csv

ticker,date,open,high,low,close,vol
AAPL,201906030900,176.32,176.32,176.24,176.29,2247
ABCD,202002211000,220.97,217.38,221.43,219.82,8544

code

import pandas as pd

df = pd.read_csv('data.csv')

# print(df)

df['time'] = df['date'].apply(lambda x: f'{str(x)[-4:-2]}:{str(x)[-2:]}')
df['date'] = df['date'].apply(lambda x: str(x)[:-4])

cols = df.columns.to_list()
cols = cols[:2] + cols[-1:] + cols[2:-1]

df = df[cols]

# print(df)

df.to_csv('out.csv', index=False)

output.csv

ticker,date,time,open,high,low,close,vol
AAPL,20190603,09:00,176.32,176.32,176.24,176.29,2247
ABCD,20200221,10:00,220.97,217.38,221.43,219.82,8544

You can use the same code to loop over multiple files.