在python中附加数据框 [英] Appending dataframes in python

问题描述

Append在python中使用for循环不起作用

Append is not working using for loop in python

没有for循环就可以使用，但是没有for循环就可以使用

It is working without for loop but It's not working using for loop

import os as o
import pandas as pd
j=0
ls=[]
files = o.listdir("demo")
for i in files:
  ls.append(i)
df=pd.read_csv("demo/"+ls[0])
t=len(ls)
for i in range(1,t):
  temp=pd.read_csv("demo/"+ls[i])
  df.append(temp,ignore_index = True)
print(df)

推荐答案

使用df.append效率很低，应该改为

Using df.append is highly inefficient, you should instead

dfs = [pd.read_csv("demo/"+ls[i]) for i in range(1, len(ls))]
df = pd.concat(dfs)

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