How to make python extract one row every seven rows from a .csv dataset?
I have a dataset of 4 columns and 15000 rows, and I need to extract one row for every seven rows i.e 1, 7, 14, ...
1) Read the .csv file as a dataframe (df) in Python.
2) Use iloc function, which takes a row/column slice, both based on integer position. So, if you want every 7th row the syntax looks like:
>> df.iloc[::7, :]
If you are looking to extract every seventh row, starting at the second row then,
>> df.iloc[1::7, :]
I hope this helps.
Best of luck!
Thank you very much Shangharsha Thapa,
I don't have much experience in Python, I ask you another question:
I have loaded 3 separate data sets:
import pandas as pd
datos1 = pd.read_csv('datos1cut.csv', header=0, skiprows=[1,2], dtype=np.float64)
datos2 = pd.read_csv('datos2.csv', header=0, skiprows=[1,2], dtype=np.float64)
datos3 = pd.read_csv('datos3.csv', header=0, skiprows=[1,2], dtype=np.float64)
How should I execute the iloc function for each set? Should I import another dataframe library?
Alexander Cristian Resentera You don't need to import library every time you use the methods within its library. Just import it at the beginning and you are done. To execute iloc function, write this script just below the script you have shown above:
selected_datos1 = datos1.iloc[::7, :]
selected_datos2 = datos2.iloc[::7, :]
selected_datos3 = datos3.iloc[::7, :]
Execute these lines of codes and the extracted every 7th rows will be within the variables that you declared (in this case selected_datos1, selected_datos2, and selected_datos3).
This is a very handy library in python to work with large excel sheets, text files. So, I suggest you to go through this link to learn more about it: https://www.tutorialspoint.com/python_pandas/python_pandas_dataframe.htm
Best Regards,
Shangharsha
- Badges
- Science topic
- Similar topics
- Phytochemistry
- Extracts