从文件中删除注释行

Question

I'm making a file type to store information from my program. The file type can include lines starting with #, like:

# This is a comment.

As shown, the # in front of a line denotes a comment. I've written a program in Python that can read these files:

fileData = []

file = open("Tutorial.rdsf", "r")

line = file.readline()

while line != "":
    fileData.append(line)
    line = file.readline()

for item in list(fileData):
   item.strip()

fileData = list(map(lambda s: s.strip(), fileData))

print(fileData)

As you can see, it takes the file, adds every line as an item in a list, and strips the items of \\n. So far, so good.

But often these files contain comments I've made, and such the program adds them to the list.

Is there a way to delete all items in the list starting with #?

Edit: To make things a bit clearer: Comments won't be like this:

Some code:
{Some Code}    #Foo

They'll be like this:

#Foo
Some code:
{Some Code}

Answer 1

You can process lines directly in a for loop:

with open("Tutorial.rdsf", "r") as file:
    for line in file:
        if line.startswith('#'):
            continue  # skip comments
        line = line.strip()

        # do more things with this line

Only put them into a list if you need random access (eg you need to access lines at specific indices).

I used a with statement to manage the open file, when Python reaches the end of the with block the file is automatically closed for you.

Answer 2

It's easy to check for leading # signs.

Change this:

while line != "":
    fileData.append(line)
    line = file.readline()

to this:

while line != "":
    if not line.startswith("#"):
        fileData.append(line)
    line = file.readline()

But your program is a bit complicated for what it does. Look in the documentation where it explains about for line in file: .