Read multiple csv files from multiple folders in Python - python

I have a folder that includes folders and these folders include many csv files. I want to import and concatenate all of them in Python.
Let's say main folder: /main
subfolders: /main/main_1
csv: /main/main_1/first.csv
path='/main'
df_list = []
for file in os.listdir(path):
df = pd.read_csv(file)
df_list.append(df)
final_df = df.append(df for df in df_list)

What about this:
import pandas as pd
from pathlib import Path
directory = "path/to/root_dir"
# Read each CSV file in dir "path/to/root_dir"
dfs = []
for file in Path(directory).glob("**/*.csv"):
dfs.append(pd.read_csv(file))
# Put the dataframes to a single dataframe
df = pd.concat(dfs)
Change the path/to/root_dir to where ever your CSV files are.

I found a way to concat all of them but it doesn't satisfy to me as it takes too much time due to computational complexity.
path = "/main"
folders = []
directory = os.path.join(path)
for root,dirs,files in os.walk(directory):
folders.append(root)
del folders[0]
final = []
for folder in folders:
df = pd.concat(map(pd.read_csv, glob.glob(os.path.join(folder + "/*.csv"))))
final.append(df)

Remember to add back main to the path:
df =pd.read_csv(path + "/" + file)

Related

Merge CSV files in different folders using Python

I have about 5600 directories structured as follows:
I need to merge all A files into one file, all B files into another file, and so on.
How can I do this?
IIUC, this should work for your case (I used a RootDir with 2 subdirectories Dir1 and Dir2 with in each 2 files A.csv and B.csv). You can change the value of rootdir to match your usecase:
import os
import pandas as pd
rootdir = 'RootDir' # Change when needed to your root directory
files = [os.path.join(dp, f) for dp, dn, filenames in os.walk(rootdir) for f in filenames if os.path.splitext(f)[1] == '.csv']
names = set([x.rstrip('.csv').split('/')[-1] for x in files])
df_dict = {key: pd.DataFrame() for key in names}
for file in files:
key = file.rstrip('.csv').split('/')[-1]
df = pd.read_csv(file)
df_dict[key] = pd.concat([df_dict[key], df])
Output is a dictionary of dataframes df_dict with A and B as keys.
Use df_dict['A'] to access DataFrame A and so on...

How to upload all csv files that have specific name inside filename in python

I want to concat all csv file that have this specific word 'tables' on the filename.
Below code is upload all csv file without filter the specific word that i want.
# importing the required modules
import glob
import pandas as pd
# specifying the path to csv files
#path = "csvfoldergfg"
path = "folder_directory"
# csv files in the path
files = glob.glob(path + "/*.csv")
# defining an empty list to store
# content
data_frame = pd.DataFrame()
content = []
# checking all the csv files in the
# specified path
for filename in files:
# reading content of csv file
# content.append(filename)
df = pd.read_csv(filename, index_col=None)
content.append(df)
# converting content to data frame
data_frame = pd.concat(content)
print(data_frame)
example filename are:
abcd-tables.csv
abcd-text.csv
abcd-forms.csv
defg-tables.csv
defg-text.csv
defg-forms.csv
From the example filenames. The expected output is concat filenames
abcd-tables.csv
defg-tables.csv
into single dataframe. Assuming the header are same.
*Really appreciate you guys can solve this
You can use:
import pandas as pd
import pathlib
path = 'folder_directory'
content = []
for filename in pathlib.Path(path).glob('*-tables.csv'):
df = pd.read_csv(filename, index_col=None)
content.append(df)
df = pd.concat(content, ignore_index=True)

Search (in folders and subfolders ) and read files to a list of dataframes, using Python

I have a code
df1 = pd.read_excel('DIRECTORY\\file.xlsm', sheetname='Resume', header=1, usecols='A:I')
#some operations
bf1 =pd.read_excel('DIRECTORY\\file.xlsm', sheetname='Resume', header=1, usecols='K:P')
#some operations
Final_file = pd.concat([df1,bf1], ignore_index=True)
Note that df and bf are reading the same file, the difference is the columns being read.
I have a lot of files.
Is it possible to go through folders and subfolders, search for a filename pattern and create a list of dataframes to read, instead of writing each path I have?
you can use a recursive method with both pathlib and glob
note parent_path should be the top level folder you want to search.
from pathlib import Path
files = [file for file in Path(parent_path).rglob('*filename*.xls')]
this will return a list of files that match your condition. you can then cocnat a list comp.
dfs = [ pd.read_excel(file, sheet_name='Resume', header=1, usecols='A:I') for file in files]
df1 = pd.concat(dfs)
Edit Latest File by Modified Time.
We can use the following function to take in a path and return a list of pathlib objects to get the latest modified time, we do this by splitting on a delimiter to get a unique file so sales_v1, sales_v2, sales_v3 will all become sales. We then get the latest modified file from the three.
import pandas as pd
from pathlib import Path
def get_latest_files(path):
files = {
f: pd.Timestamp(f.stat().st_mtime, unit="s") for f in Path(path).rglob("*.csv")
}
df = (
pd.DataFrame.from_dict(files, orient="index")
.reset_index()
.rename(columns={"index": "path", 0: "seconds"})
)
df["dupe_files"] = df["path"].apply(lambda x: x.stem).str.split("_", expand=True)[0]
max_files = (
df.groupby(["dupe_files", "path"])
.max()
.groupby(level=0)["seconds"]
.nlargest(1)
.to_frame()
.reset_index(-1)["path"]
.tolist()
)
return max_files
Here is a code snippet that might help your cause:-
source = r'C:\Mypath\SubFolder'
for root, dirs, files in os.walk(source):
for name in files:
if name.endswith((".xls", ".xlsx",".xlsm")):
filetoprocess=os.path.join(root,name)
df=pd.read_excel(filetoprocess, sheetname='Resume', header=1, usecols='A:I')
Hope that helps.
You can use glob library to do this -
from glob import glob
filenames = glob('./Folder/pattern*.xlsx') #pattern is the common pattern in filenames
dataframes = [pd.read_excel(f) for f in filenames] #sequentially read all the files and create a dataframe for each file
master_df = pd.concat(dataframes) #master dataframe after concatenating all the dataframes

How to merge 2000 CSV files saved in different subfolders within the same main folder

Hey People I would like to merge 2000 Csv files into one of 2000 sub-folders. Each sub-folder contains three Csv files with different names. so I need to select only one Csv from each folder.
I know the code for how to merge bunch of Csv files if they are in the same - folder.
import pandas as pd
import glob
path = r'Total_csvs'
all_files = glob.glob(path + "/*.csv")
li = []
for filename in all_files:
df = pd.read_csv(filename, index_col=None, header=0)
li.append(df)
frame = pd.concat(li, axis=0, ignore_index=True)
frame.to_csv('Total.csv',index=False)
But my problems with 2000 Csv files look totally different.
Folder structure is:
Main folder (with in this 2000 subfolders, within subfolders I had multiple Csv Files and I need to select only one Csv file from this. Finally concating all 2000 Csv files.)
Coming to Naming Conventions (all the subfolders had different names, but the subfolder name and the Csv name within the subfolder is same)
Any suggestions or a sample code (how to read 2000 Csv from sub-folders) would be helpful.
Thanks in advance
You can loop through all the subfolders using os.listdir.
Since the CSV filename is the same as the subfolder name, simply use the subfolder name to construct the full path name.
import os
import pandas
folders = os.listdir("Total_csvs")
li = []
for folder in folders:
# Since they are the same name
selected_csv = folder
filename = os.path.join(folder, selected_csv + ".csv")
df = pd.read_csv(filename, index_col=None, header=0)
li.append(df)
frame = pd.concat(li, axis=0, ignore_index=True)
frame.to_csv('Total.csv',index=False)
We can iterate on every subfolder, determine expected_csv_path, check if it exists. If it exists, we add them to our all_files list.
Try following:
import pandas as pd
import os
path = r'Total_csvs'
li = []
for f in os.listdir(path):
expected_csv_path = os.path.join(path, f, f + '.csv')
csv_exists = os.path.isfile(expected_csv_path)
if csv_exists:
df = pd.read_csv(expected_csv_path, index_col=None, header=0)
li.append(df)
frame = pd.concat(li, axis=0, ignore_index=True, sort=False)
frame.to_csv('Total.csv',index=False)
If you are using Python 3.5 or newer you could use glob.glob in recursive manner following way:
import glob
path = r'Total_csvs'
all_csv = glob.glob(path+"/**/*.csv",recursive=True)
Now all_csv is list of relative paths to all *.csv inside Total_csv and subdirectories of Total_csv and subdirectories of subdirectories of Total_csv and so on.
For example purpose lets assume that all_csv is now:
all_csv = ['Total_csvs/abc/abc.csv','Total_csv/abc/another.csv']
So we need to get files with names correnponding to directory of their residence, this could be done following way:
import os
def check(x):
directory,filename = x.split(os.path.sep)[-2:]
return directory+'.csv'==filename
all_csv = [i for i in all_csv if check(i)]
print(all_csv) #prints ['Total_csvs/abc/abc.csv']
Now all_csv is list of paths to all .csv you are seeking and you can use it same way as you did with all_csv in "flat" (non-recursive) case.
You can do it without joining paths:
import pathlib,pandas
lastparent=None
for ff in pathlib.Path("Total_csvs").rglob("*.csv"): # recursive glob
print(ff)
if(ff.parent!=lastparent): # process the 1st file in the dir
lastparent= ff.parent
df = pd.read_csv(str(ff),... )
...etc.

Retrieving data from multiple files into multiple dataframes

Scenario: I have a list of files in a folder (including the file paths). I am trying to get the content of each of those files into a dataframe (one for each file), then further perform some operations and later merge these dataframes.
From various other questions in SO, I found multiple ways to iterate over the files in a folder and get the data, but all of those I found usually ready the files in a loop and concatenate them into a single dataframe automatically, which does not work for me.
For example:
import os
import pandas as pd
path = os.getcwd()
files = os.listdir(path)
files_xls = [f for f in files if f[-3:] == 'xls*']
df = pd.DataFrame()
for f in files_xls:
data = pd.read_excel(f, 'Sheet1')
df = df.append(data)
or
import pandas as pd
import glob
all_data = pd.DataFrame()
for f in glob.glob("*.xls*"):
df = pd.read_excel(f)
all_data = all_data.append(df,ignore_index=True)
The only piece of code I could put together from what I found is:
from os.path import isfile, join
import glob
mypath = "/DGMS/Destop/uploaded"
listoffiles = glob.glob(os.path.join(mypath, "*.xls*"))
contentdataframes = (pd.read_excel(f) for f in listoffiles)
This lines run without error, but they appear not to do anything, no variables or created nor changed.
Question: What am I doing wrong here? Is there a better way to do this?
You are really close, need join all data by concat from generator:
contentdataframes = (pd.read_excel(f) for f in listoffiles)
df = pd.concat(contentdataframes, ignore_index=True)
If need list of DataFrames:
contentdataframes = [pd.read_excel(f) for f in listoffiles]

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