将目录中的csv文件另存为单独的数据框

Question

I have several files csv in the directory

What I need to do is to iterate ( specifically iterate , because I will do other calculations over the data) in the folder over the files and read them using pandas.read_csv as a separate DataFrames .

What I have wrote is the following:

for i in os.listdir(directory):
    data = pd.read_csv(directory+ '/' +i, encoding="utf8")

When I execute the code above it writes down only the last step's data in the df and when I change the code to the one below:

for i in os.listdir(directory):
    data[i] = pd.read_csv(directory+ '/' +i, encoding="utf8")

data[i] is marked by red

Could anyone help with this?

Answer 1

If you change your 2nd code snippet to be like this, then it should work, and your dictionary will have keys of the name of the file, and the values will be Dataframes of the corresponding data.

data = {}
for i in os.listdir(directory):
    data[i] = pd.read_csv(directory+ '/' +i, encoding="utf8")

# or using fancy dictionary comprehensions & f-strings (needs recent python3 release)
data = {path: pd.read_csv(f'{directory}/{path}', encoding="utf8")
    for path in os.listdir(directory)}

# or using pathlib
from pathlib import Path
data = {path.name: pd.read_csv(path, encoding="utf8"
    for path in Path(directory).iterdir()}