issues while reading a file in python - python

I'm struggling with reading a file in python, the py file and CSV file are in the same folder but the VSCode makes an error and can't find the file:
import csv
with open('file.csv','r') as f:
reader = reader(f)
...
how can I fix this??
and the error is:
Exception has occurred: FileNotFoundError
[Errno 2] No such file or directory: 'file.csv'

If you run:
import os
os.getcwd()
You'll find out your current working directory which I assume is not the one you were expecting. If you're running the python script through VS code it could be using it could be the directory which you have open on the left hand side.
So either run the python using the correct working directory or use an absolute path like this:
import csv
with open('pathname/file.csv','r') as f:
reader = reader(f)

There might be an issue with your relative path settings.
Try this:
import os
import csv
dir = os.path.dirname(__file__)
filename = os.path.join(dir, 'file.csv')
with open(filename,'r') as f:
reader = reader(f)

Are you using spyder?
If so, please check if the current working path is the path your py file locates.

import csv
with open('file.csv','r') as f:
reader = csv.reader(f)
in this case your file.csv should be in folder where is your python script (current working folder)
or, instead of 'file.csv' you can put absolute path

Related

Python doesn't find file

I'm learning Python (with Python Crash Course book) and i'm currently working with climate data from the NOAA, but everytime i try to import a file, Python does not find it. I had this error for other programs too and i can't really solve it. Could anyone help me please ?
Here's my code :
import csv
filename = 'new-york-weather_60-20.csv'
try :
with open(filename) as f:
reader = csv.reader(f)
header_row = next(reader)
print(header_row)
except FileNotFoundError:
print(f"Sorry, the file {filename} does not exist.")
The Python interpreter assumes that the file 'new-york-weather_60-20.csv' is in the same directory (folder) as where python currently 'is', i.e., the current working directory.
You can see the current working directory by using the os module.
import os
print(os.getcwd())
This should be the path in which the csv file is located. If it is not, you can either move the file into that same location, or you can move the current working directory to the path where the file is located
import os
os.chdir('/the/location/on/your/computer/wherethefileislocated')
filename = 'new-york-weather_60-20.csv'
# You can check if the file is located in this directory
if os.path.exists(filename): # only if this file exists in this location do we continue
print('The file exists!')
with open(filename) as f:
# your code goes here
else:
print('The file does not exist in this directory')

Can't read csv file in same directory [duplicate]

Say I have a Python project that is structured as follows:
project
/data
test.csv
/package
__init__.py
module.py
main.py
__init__.py:
from .module import test
module.py:
import csv
with open("..data/test.csv") as f:
test = [line for line in csv.reader(f)]
main.py:
import package
print(package.test)
When I run main.py I get the following error:
C:\Users\Patrick\Desktop\project>python main.py
Traceback (most recent call last):
File "main.py", line 1, in <module>
import package
File "C:\Users\Patrick\Desktop\project\package\__init__.py", line 1, in <module>
from .module import test
File "C:\Users\Patrick\Desktop\project\package\module.py", line 3, in <module>
with open("../data/test.csv") as f:
FileNotFoundError: [Errno 2] No such file or directory: '../data/test.csv'
However, if I run module.py from the package directory, I don’t get any errors. So it seems that the relative path used in open(...) is only relative to where the originating file is being run from (i.e __name__ == "__main__")? I don't want to use absolute paths. What are some ways to deal with this?
Relative paths are relative to current working directory.
If you do not want your path to be relative, it must be absolute.
But there is an often used trick to build an absolute path from current script: use its __file__ special attribute:
from pathlib import Path
path = Path(__file__).parent / "../data/test.csv"
with path.open() as f:
test = list(csv.reader(f))
This requires python 3.4+ (for the pathlib module).
If you still need to support older versions, you can get the same result with:
import csv
import os.path
my_path = os.path.abspath(os.path.dirname(__file__))
path = os.path.join(my_path, "../data/test.csv")
with open(path) as f:
test = list(csv.reader(f))
[2020 edit: python3.4+ should now be the norm, so I moved the pathlib version inspired by jpyams' comment first]
For Python 3.4+:
import csv
from pathlib import Path
base_path = Path(__file__).parent
file_path = (base_path / "../data/test.csv").resolve()
with open(file_path) as f:
test = [line for line in csv.reader(f)]
This worked for me.
with open('data/test.csv') as f:
My Python version is Python 3.5.2 and the solution proposed in the accepted answer didn't work for me. I've still were given an error
FileNotFoundError: [Errno 2] No such file or directory
when I was running my_script.py from the terminal. Although it worked fine when I run it through Run/Debug Configurations from the PyCharm IDE (PyCharm 2018.3.2 (Community Edition)).
Solution:
instead of using:
my_path = os.path.abspath(os.path.dirname(__file__)) + some_rel_dir_path
as suggested in the accepted answer, I used:
my_path = os.path.abspath(os.path.dirname(os.path.abspath(__file__))) + some_rel_dir_path
Explanation:
Changing os.path.dirname(__file__) to os.path.dirname(os.path.abspath(__file__))
solves the following problem:
When we run our script like that: python3 my_script.py
the __file__ variable has a just a string value of "my_script.py" without path leading to that particular script. That is why method dirname(__file__) returns an empty string "". That is also the reason why my_path = os.path.abspath(os.path.dirname(__file__)) + some_rel_dir_path is actually the same thing as my_path = some_rel_dir_path. Consequently FileNotFoundError: [Errno 2] No such file or directory is given when trying to use open method because there is no directory like "some_rel_dir_path".
Running script from PyCharm IDE Running/Debug Configurations worked because it runs a command python3 /full/path/to/my_script.py (where "/full/path/to" is specified by us in "Working directory" variable in Run/Debug Configurations) instead of justpython3 my_script.py like it is done when we run it from the terminal.
Try
with open(f"{os.path.dirname(sys.argv[0])}/data/test.csv", newline='') as f:
I was surprised when the following code worked.
import os
for file in os.listdir("../FutureBookList"):
if file.endswith(".adoc"):
filename, file_extension = os.path.splitext(file)
print(filename)
print(file_extension)
continue
else:
continue
So, I checked the documentation and it says:
Changed in version 3.6: Accepts a path-like object.
path-like object:
An object representing a file system path. A path-like object is
either a str or...
I did a little more digging and the following also works:
with open("../FutureBookList/file.txt") as file:
data = file.read()

Django can't find a file stored in my application folder

I have a folder that stores a json file in my django application folder, ie, test_data/data.json.
In my tests.py, I am trying to read this file using the following code:
with open('/test_data/data.json', 'r') as f:
self.response_data = json.load(f)
However, I keep on getting the following error:
FileNotFoundError: [Errno 2] No such file or directory: '/test_data/data.json'
What am I doing wrong? Thanks.
Edit: I tried removing the leading slash, yet I still get the same error.
import os
try this
with open(os.getcwd() + '/test_data/data.json', 'r') as f:
self.response_data = json.load(f)
If you're opening files in directories close to where your code is, it is common to place
import os
DIRNAME = os.path.dirname(__file__) # the directory of this file
at the top of the file.
Then you can open files in a test_data subdirectory with
with open(os.path.join(DIRNAME, 'test_data', 'data.json'), 'rb') as fp:
self.response_data = json.load(fp)
you probably want to open json files, which should be utf-8 encoded, in 'rb' (read-binary) mode.

Relative file paths in python [duplicate]

Say I have a Python project that is structured as follows:
project
/data
test.csv
/package
__init__.py
module.py
main.py
__init__.py:
from .module import test
module.py:
import csv
with open("..data/test.csv") as f:
test = [line for line in csv.reader(f)]
main.py:
import package
print(package.test)
When I run main.py I get the following error:
C:\Users\Patrick\Desktop\project>python main.py
Traceback (most recent call last):
File "main.py", line 1, in <module>
import package
File "C:\Users\Patrick\Desktop\project\package\__init__.py", line 1, in <module>
from .module import test
File "C:\Users\Patrick\Desktop\project\package\module.py", line 3, in <module>
with open("../data/test.csv") as f:
FileNotFoundError: [Errno 2] No such file or directory: '../data/test.csv'
However, if I run module.py from the package directory, I don’t get any errors. So it seems that the relative path used in open(...) is only relative to where the originating file is being run from (i.e __name__ == "__main__")? I don't want to use absolute paths. What are some ways to deal with this?
Relative paths are relative to current working directory.
If you do not want your path to be relative, it must be absolute.
But there is an often used trick to build an absolute path from current script: use its __file__ special attribute:
from pathlib import Path
path = Path(__file__).parent / "../data/test.csv"
with path.open() as f:
test = list(csv.reader(f))
This requires python 3.4+ (for the pathlib module).
If you still need to support older versions, you can get the same result with:
import csv
import os.path
my_path = os.path.abspath(os.path.dirname(__file__))
path = os.path.join(my_path, "../data/test.csv")
with open(path) as f:
test = list(csv.reader(f))
[2020 edit: python3.4+ should now be the norm, so I moved the pathlib version inspired by jpyams' comment first]
For Python 3.4+:
import csv
from pathlib import Path
base_path = Path(__file__).parent
file_path = (base_path / "../data/test.csv").resolve()
with open(file_path) as f:
test = [line for line in csv.reader(f)]
This worked for me.
with open('data/test.csv') as f:
My Python version is Python 3.5.2 and the solution proposed in the accepted answer didn't work for me. I've still were given an error
FileNotFoundError: [Errno 2] No such file or directory
when I was running my_script.py from the terminal. Although it worked fine when I run it through Run/Debug Configurations from the PyCharm IDE (PyCharm 2018.3.2 (Community Edition)).
Solution:
instead of using:
my_path = os.path.abspath(os.path.dirname(__file__)) + some_rel_dir_path
as suggested in the accepted answer, I used:
my_path = os.path.abspath(os.path.dirname(os.path.abspath(__file__))) + some_rel_dir_path
Explanation:
Changing os.path.dirname(__file__) to os.path.dirname(os.path.abspath(__file__))
solves the following problem:
When we run our script like that: python3 my_script.py
the __file__ variable has a just a string value of "my_script.py" without path leading to that particular script. That is why method dirname(__file__) returns an empty string "". That is also the reason why my_path = os.path.abspath(os.path.dirname(__file__)) + some_rel_dir_path is actually the same thing as my_path = some_rel_dir_path. Consequently FileNotFoundError: [Errno 2] No such file or directory is given when trying to use open method because there is no directory like "some_rel_dir_path".
Running script from PyCharm IDE Running/Debug Configurations worked because it runs a command python3 /full/path/to/my_script.py (where "/full/path/to" is specified by us in "Working directory" variable in Run/Debug Configurations) instead of justpython3 my_script.py like it is done when we run it from the terminal.
Try
with open(f"{os.path.dirname(sys.argv[0])}/data/test.csv", newline='') as f:
I was surprised when the following code worked.
import os
for file in os.listdir("../FutureBookList"):
if file.endswith(".adoc"):
filename, file_extension = os.path.splitext(file)
print(filename)
print(file_extension)
continue
else:
continue
So, I checked the documentation and it says:
Changed in version 3.6: Accepts a path-like object.
path-like object:
An object representing a file system path. A path-like object is
either a str or...
I did a little more digging and the following also works:
with open("../FutureBookList/file.txt") as file:
data = file.read()

opening a file without an extension python

I would like to open a file called "summary" and read information out of it to write into an output file, however I cannot open "summary"
I have tried to verify that the path exists - which works:
import os.path
print os.path.exists('/Users/alli/Documents/Summer2016/sfit4_trial/summary')
This prints out true. However when I try to do
import os
import glob
path = '/Users/alli/Documents/Summer2016/sfit4_trial/summary'
for infile in glob.glob(os.path.join(path, '*')):
file = open(infile, 'r').read()
print file
Nothing happens. I have looked through similar questions on SO and tried them all but not having any luck. All suggestions welcome. Thanks.
Have you tried?
...
path = '/Users/alli/Documents/Summer2016/sfit4_trial'
for infile in glob.glob(os.path.join(path, 'summary*')):
...

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