delete a line in .txt using python by matching the number in the line

I finally came to my last part.. and I'm stuck..

In my orderlist.txt file I have

[99 ,1, "3/03/2011", ["ScrewDriver", "Hammer", "Stone"]]
[2 ,2, "3/03/2011", ["hammer,nails"]]
[31 ,2, "3/03/2011", ["plaster,studd"]]
[100 ,2, "开发者_开发百科3/03/2011", ["hammer,studd"]]

my code:

def delorder():
    f=open('orderlist.txt',"r+")
    lines=f.readlines()
    num_del=int(input("what is the ordernumber to be deleted:"))
    new=""

    for line in lines:
        listline=eval(line)
        if not(num_del==list_line[0]):
            new +=(line + "\n")
        return (new)

at this part it give me

Traceback (most recent call last):
  File "E:/cscs 120 testint in lab/assignment 1/Customer assignment 1/Customer assignment 1/testing oder", line 13, in <module>
    print(delorder())
  File "E:/cscs 120 testint in lab/assignment 1/Customer assignment 1/Customer    assignment 1/testing oder", line 8, in delorder
    listline=eval(line)
  File "<string>", line 1
    [99 ,1, "3/03/2011", [“ScrewDriver”, “Hammer”, “Stone”]]
                                      ^
SyntaxError: invalid character in identifier

My objective of this function is to get an input number example:31 and it will delete--> [31 ,2, "3/03/2011", ["plaster,studd"]], which at the end in the orderlist.txt it would not appearr this line [31 ,2, "3/03/2011", ["plaster,studd"]] but the left over lines. plz help

I'm not sure if you see them, but look closely at those quotation marks:

[1,'1','3/03/2011', [“ScrewDriver”, “Hammer”, “Stone”]]

There's a difference between this:

”

and this:

"

The first one (”) is a curly quote, which screws up the interpreter. Use normal quotes (") and post back what your script returns then.

Also, what does this return statement do:

return (new)

If you're in a function, the function will quit upon the first iteration of the list, as it returns every single loop, but only the first one is caught and the function dies there.

I'd move the return statement down a level so it isn't part of the for loop. So change this:

for line in lines:
    listline=eval(line)
    if not(num_del==list_line[0]):
        new +=(line + "\n")
    return (new)

To this:

for line in lines:
    listline=eval(line)
    if not(num_del==list_line[0]):
        new +=(line + "\n")

return (new)

This is your text file without the curly quotes. Try copy and pasting it:

[99 ,1, "3/03/2011", ["ScrewDriver", "Hammer", "Stone"]]
[2 ,2, "3/03/2011", ["hammer,nails"]]
[31 ,2, "3/03/2011", ["plaster,studd"]]
[100 ,2, "3/03/2011", ["hammer,studd"]]