CODEWITHSUNDEEP
pythonlist
ValientProcess
ValientProcess

Reputation: 1801

Creating a list of missing files after reading paths from another list

I have a list of file paths listt:

['/data0/river_routes.nc',
 '/dat/rho0_profile.nc',...]

I want to check if they exist, and if not - create a list list1 with just the paths of the missing files.

I can create list1 full of True/False using:

import os,time
list1 = []
for file in listt:
    list1.append(os.path.isfile(file))

But I'm not sure how to create a list of the missing paths in the most efficient way

Upvotes: 0

Views: 118

Answers (4)

Jab
Jab

Reputation: 27495

You need to append the path not the bool that isfile returns. 

from os.path import isfile

paths = ['/data0/river_routes.nc', '/dat/rho0_profile.nc',...]

missing_paths = []
for path in paths:
    if not isfile(path):
        missing_paths.append(path)

This can also be done using a list comprehension:

missing_paths = [path for path in paths if not isfile(path)]

Or you can use itertools.filterfalse:

from itertools import filterfalse as ffilter
missing_paths = list(filter(ispath, paths))

Upvotes: 2

Kamrus
Kamrus

Reputation: 364

you can use list comprehension 

import os

not_exists = [f for f in list1 if not os.path.exists(f)]

where list1 is list with paths

Upvotes: 1

Kshitij Saxena
Kshitij Saxena

Reputation: 940

Just subtract a set of found from all:

import os
path = 'path/to/directory'
listt = ['/data0/river_routes.nc',
         '/dat/rho0_profile.nc',...]
all = set(listt)
found = set(os.listdir(path))
missing = list(all - found)

Upvotes: 1

abdusco
abdusco

Reputation: 11091

Try this one:

from pathlib import Path

if __name__ == '__main__':
    paths = ['/data0/river_routes.nc',
             '/dat/rho0_profile.nc']
    missing = []
    for item in paths:
        p = Path(item)
        if not p.exists():
            missing.append(item)

Upvotes: 2

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