使用pandas从python中的现有csv文件生成新csv文件的指定数字数据帧的方法

Question

I have large data-frame in a Csv file sample1 from that i have to generate a new Csv file contain only 100 data-frame.i have generate code for it.but i am getting key Error the label[100] is not in the index? I have just tried as below,Any help would be appreciated

import pandas as pd
data_frame = pd.read_csv("C:/users/raju/sample1.csv")
data_frame1 = data_frame[:100]
data_frame.to_csv("C:/users/raju/sample.csv")`

`

Answer 1

The correct syntax is with iloc :

data_frame.iloc[:100]

A more efficient way to do it is to use nrows argument who purpose is exactly to extract portions of files. This way you avoid wasting resources and time parsing useless rows:

import pandas as pd
data_frame = pd.read_csv("C:/users/raju/sample1.csv", nrows=101)  # 100+1 for header
data_frame.to_csv("C:/users/raju/sample.csv")