DataFrame to CSV in a for loop with different file names

Question

I am creating pandas DataFrames in a for loop and I would like to save them in csv files with different names at each iteration of the for loop.

I know how to save one DataFrame:

path = r"C:\Users\SessionName\FolderName\FileName.csv"
df.to_csv(path)

Now when I have a list of strings, e.g.

countries = ['United States', 'China', 'Russia', 'India']

I would like the four files to be named United States_ranking.csv, China_ranking.csv, etc.

I have tried:

for country in countries:
    path = r"C:\Users\SessionName\FolderName\" + country + "_ranking.csv"

But is won't work.

do you want the csvs to be exactly the same ? is there a country column you can group on first ? — Umar.H
– Umar.H, Commented Oct 22, 2020 at 9:48
Do you have the "df.to_cvs(path)" line inside your for-loop? — Carl
– Carl, Commented Oct 22, 2020 at 9:54

Dejene T. · Accepted Answer · 2020-10-22 09:57:47Z

2

use this:

for country in countries:
    path = r"C:\\Users\\SessionName\\FolderName\\ {} _ranking.csv".format(country)

answered Oct 22, 2020 at 9:57

Dejene T.

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Comments

Umar.H · Accepted Answer · 2020-10-22 10:04:07Z

2

personally, I would use pathlib to handle your paths. also be careful for typos in your code.

for example,

import pandas as pd
from pathlib import Path

src_path  = r"C:\Users\SessionName\FolderName\FileName.csv"
countries = ['United States', 'China', 'Russia', 'India']

for country in countries:
    p = Path(src_path).parent.joinpath(f"{country}_ranking.csv")
    df.to_csv(p,index=False)

this will write:

C:\Users\SessionName\FolderName\United States_ranking.csv
C:\Users\SessionName\FolderName\China_ranking.csv
C:\Users\SessionName\FolderName\Russia_ranking.csv
C:\Users\SessionName\FolderName\India_ranking.csv

The benefit of having a pathlib object here is that you can check if the directory is valid or if the file exists before hand.

print(p)
WindowsPath('C:/Users/SessionName/FolderName/United States_ranking.csv')
if not p.is_file():
   df.to_csv(p,index=False)
else:
    print('file exists')

edited Oct 22, 2020 at 10:04

answered Oct 22, 2020 at 9:56

Umar.H

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1 Comment

Umar.H Over a year ago

@jezrael I think so too, but OP hasn't shown the structure of CSV so don't want to assume

lauriane.g · Accepted Answer · 2020-10-22 09:55:05Z

0

You have to write the path like this, otherwise it causes a problem with "\"

for country in countries:
    path = r"C:\\Users\\SessionName\\FolderName\\" + country + "_ranking.csv"

edited Oct 22, 2020 at 9:55

answered Oct 22, 2020 at 9:50

lauriane.g

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2 Comments

Carl Over a year ago

He/she uses a raw string, so thats not it.

lauriane.g Over a year ago

No, the raw string doesn't work for strings which end with one '\'.

辜乘风 · Accepted Answer · 2020-10-22 09:57:28Z

0

I prefer os.path.join(folder, country+filename)

for country in countries:
    path = os.path.join("C:\\Users\\SessionName\\FolderName\\", country + "_ranking.csv")
    df.loc[df.country == country].to_csv(path)

answered Oct 22, 2020 at 9:57

辜乘风

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Comments

Salamander Krajza · Accepted Answer · 2020-10-22 09:59:52Z

0

Looks like rawstring dont work with "\" and the end of the string.

You can fix it by adding extra \ after your path to folder by puting double "\\" in another string.

countries = ['United States', 'China', 'Russia', 'India']
for country in countries:
    path = r"C:\Users\SessionName\FolderName" + "\\" + country + "_ranking.csv"

answered Oct 22, 2020 at 9:59

Salamander Krajza

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