为什么不从文件中打印单行？

Question

As part of a bigger project, I would simply like to make sure that a file can be opened and Python can read and use it. So after I opened up the txt file, I said:

data = txtfile.read()

first_line = data.split('\n',1)[2]

print(first_line)

I also tried

print(f1.readline())

where f1 is the txt file. This, again, did nothing. I am using the spyder IDE, and it just says running file, and doesn't print anything. Is it because my file is too large? It is 4.6 gigs.

Does anyone have any idea what's going on?

Answer 1

and it just says running file, and doesn't print anything. Is it because my file is too large? It is 4.6 gigs.

Yes.

data = txtfile.read()

This function is going to read the entire file. Since you stated that the file is 4.6GB, it is going to take time to load the entire file and then split the by newline character.

See this: Read large text files in Python

I don't know your context of use, so, if you can process line by line, it would be simpler. Or even chunks would make it simpler than reading the entire file.

Answer 2

This should work:

with open('file-name') as f:
    print(f.readline())

Answer 3

first_line =  open('myfile.txt', 'r').readline()