IOError: [Errno 2] No such file or directory: '0.txt'

I am writing a program to read a set of text files from folder "set" to a list.My code for this is

def get_documents():
    path1 = "D:/set/"
    texts = []
    listing1 = os.listdir(path1)
    for file in listing1:
        with open(file,'r') as f:
            lines = f.read().splitlines()
            texts.append(lines)

But this gives me Error as

with open(file,'r') as f:
IOError: [Errno 2] No such file or directory: '0.txt'

There are text files inside D:/set/ namely 0.txt,1.txt,2.txt... What is the reason for this Error?