How to read input file for correct int list? python, list,

Question

My input is a list of int elements where I save the list as a file (not more, not less), which works fine so far. But when it comes to taking the file as an input for my int list, I either get wrong list elements or an error for the code. The numbers can be any (positive) int and it's an even number.

input for file (by keyboard):

1, 2, 3, 4

file content:

[1, 2, 3, 4]

list after input from file:

['[1', '2', '3', '4]']

where it should be:

[1, 2, 3, 4]

The elements of my filst from file need to be int again.

l = list_from_file
a = 0
l [ 1 ] = 2

def take ( profil , s , succ) :
    a = 0
    j = 0
    n = 0
    erf = False
    if s :
        print ( "\nPut your list in." )# supposed to be a list
        profil = [ int ( x ) for x in input ( ).split ( sep = ', ' ) ]
        s = False
    else :
        profil = input ( "\nPut your list in. Again." ).split ( sep = ', ' )
    erf = check( profil )
    if not erf :
        erf = ask ( profil , s , succ)
    return profil , s

def check( profil ) :
    a = 0
    b = True
    n = 0
    for n in profil [ : ] :
#        if  int ( profil [ n ] ) < 0 : #Some confusing errors I tried to fix with these possibilities...
#        if  profil [ n ] < 0 :
        if  int ( n ) < 0 :
#        if  n < 0 :
            b = False
            exit
        a += 1
    a -= 1
    if ( profil [ -1 ] != profil [ a ] ) : 
        b = False
    return b
def ask( profil , s , succ) :
    show( profil , succ)
    s = check( profil )
    if s :
        profil = input ( "\nPut your list in." ).split ( sep = ', ' )        
        s = False
    else :
        profil = input ( "\nPut your list in. Again." ).split ( sep = ', ' )
#    if profil [ 0 ] != 0 :
#        s = ask
    return succ, s

def save( profil , path) :
    path = input ( "Put your path in: " )
    erf = False
    if os.path.isfile ( path) : 
        inp= input ( "File already exists. Overwrite[u], bring as input [e] or ignore[i]?" )
        if inp== 'u' or inp== 'U' :
            f = open ( path, "w" )
            f.write ( str ( profil ) )
        elif inp== 'e' or inp== 'E' :
            f = open ( path, "r" )                                                  
            profil = f.read ( ).split ( sep = ', ' ) 
        elif inp== 'i' or inp== 'I' :
            f = open ( path, "r" )                                             
            print ( "File closed." )
            f = f.close
        else :
            inp= input ( "Confusing input. Continue with any key." )
            return profil
    else :
        print ( "File made." )
        f = open ( path, "w" )
        f.write ( profil )
        f = f.close
    return profil
def bring( path, profil ) :
    path= input ( "\nPath: " )    
    f = open ( path, "r" )
    profil = f.read ().split ( sep = ', ' )
#    profil = [ int ( x ) for x in input ( ).split ( sep = ', ' ) ]
#    profil = profil ().read().replace ( '[' , '' )
#    profil = f.read [ : ].replace ( ']' , '' )#also some variants I tried.
    f = f.close
#    profil = strrep ( profil )#new function I tried to
    print (profil)
    return profil


def delete ( path, succ) :
    erf = False
    path= input ( "Put in deleting path." )
    if os.path.isfile ( path) :
        os.remove ( path)
                print ( "File " + path+ " deleted." )
        erf = True
    else :
        print ( "Datei nicht gefunden." )
    return erf

inp = input("Please start.")
while ( inp != 'q' ) and ( inp != 'Q' ) :
    elif inp == 'N' :
        inp = input ( "and now?" )
    elif inp == 'p' or inp == 'P' :  
        profil , s = take ( profil , s , succ )
        succ = zeigen ( profil , succ )
        if profil [ 0 ] == '0' :
            print ( "Profil not usable.." )
        else :
            inp = input ( "and now?" )
    elif inp == 'z' or inp == 'Z' :
        succ = show ( profil , succ )
        inp = 'N'
    elif inp == 's' or inp == 'S' :
        profil = save ( profil , path )
        inp = 'N'
    elif inp == 'e' or inp == 'E' :
        profil = bring( path , profil )
        print(profil )
        dif = profil [ 0 ]
        inp = 'N'
    elif inp == 'l' or inp == 'L' :
        succ = delete ( path , succ )
        inp = 'N'
    else :
        inp = input ( "unknown command. Quit with Q..." )
if ( inp == 'q' ) or ( inp == 'Q' ) :
    quit ( )

Can you please paste the exact code you are using?

Avión
– Avión

2017-07-26 09:10:19 +00:00
Commented Jul 26, 2017 at 9:10 — Avión
– Avión, Commented Jul 26, 2017 at 9:10
That will be anything but a MWE...

muggi
– muggi

2017-07-26 09:11:15 +00:00
Commented Jul 26, 2017 at 9:11 — muggi
– muggi, Commented Jul 26, 2017 at 9:11
So make a mcve and we'll help you.

Avión
– Avión

2017-07-26 09:11:39 +00:00
Commented Jul 26, 2017 at 9:11 — Avión
– Avión, Commented Jul 26, 2017 at 9:11

DeepSpace · Accepted Answer · 2017-07-26 11:04:23Z

1

You have several options here.

Save each number in its own line instead of the actual list, then in order to read the file to a list of ints:
```
with open(filename) as f:
    list_of_ints = [int(line.strip()) for line in f]
```

If you insist on writing the list as-is to the file, you can use literal_eval (do not use eval):

from ast import literal_eval

with open(filename) as f:
    list_of_ints = literal_eval(f.read().strip())

Keep in mind my usage of strip() to get rid of possible leading/trailing spaces and/or new line characters.

edited Jul 26, 2017 at 11:04

answered Jul 26, 2017 at 9:13

DeepSpace

82.2k12 gold badges119 silver badges166 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

muggi Over a year ago

first solution gives error back [Invalid literal for int() with base 10], second works fine (for what I see).

DeepSpace Over a year ago

@Nepumuk As I explain in the answer, the first solution will only work if the file contains numbers in individual lines.

Ashraf Abdul · Accepted Answer · 2017-07-26 09:13:24Z

0

If you are saving the list to a file and assuming list_from_file is the string representation that has been read. Use ast to evaluate the list.

import ast
l = ast.literal_eval(list_from_file)

answered Jul 26, 2017 at 9:13

Ashraf Abdul

211 bronze badge

1 Comment

Ashraf Abdul Over a year ago

From the ast docs, this only works for "Python literal structures: strings, numbers, tuples, lists, dicts, booleans, and None". If you want such a functionality for other objects you should try Pickling.

Collectives™ on Stack Overflow

How to read input file for correct int list? python, list,

2 Answers 2

2 Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related