What does the following code do? <pre> f = open("test.txt") </pre>

Correct. The open() function opens a file, and returns it as a file object. By default, when only the filename is passed, the open function opens the file in read mode.

What does the following code do? <pre> f = open("test.txt", "r+") </pre>

Correct. The mode “r+” is for reading and writing.

What is the result of the following code? <pre> lst = [] with open("text.txt", "r") as f: lines = f.readlines() for i in range(2): lst.append(lines[i].rstrip()) print(lst) </pre> If we have a file “text.txt” with the following content? <img src="http://reaskly.com/wp-content/uploads/2022/08/RBqQGa37S5SakBmt-yuUmw_7b2a0c683650645666fc90201e7c9134_Screen-Shot-2020-02-28-at-12.33.11-PM.png" alt="Reaskly Question">

Correct. The readlines() method reads all lines in the file as a list. The range(2) generates a sequence from 0 to 1. We iterate through the sequence and get the first and second line in the list (file). The rstrip() method removes the ‘\n’ at the end of each line, and the method append() adds the line to result lst.

Quiz 8 - File I/O » Week 4 » Introduction To Python Programming

Q: What will happen if you run the following code, but "test.txt" does not exist? <pre> f = open("test.txt", "a") </pre.

Correct. When you open the file with append mode “a”, the write position will always be at the end of the file, and it creates the file if it doesn’t exist.

Q: Which of the following commands can be used to read all of the content in a file object f as a string?

Correct. The read() method reads an entire file as a string.

Q: What is the result of the following code? <pre> with open("text.txt", "w") as f_write: f_write.write("That is the wisdom of life.") with open("text.txt", "r") as f_read: line = f_read.readline() print(line) </pre> If we have a file “text.txt” with following content? <img src="http://reaskly.com/wp-content/uploads/2022/08/RBqQGa37S5SakBmt-yuUmw_7b2a0c683650645666fc90201e7c9134_Screen-Shot-2020-02-28-at-12.33.11-PM.png" alt="Reaskly Question">

Correct. The method write() writes from the start of the file, so the first line in the file will be overwritten by the new line. The method readline() reads the first line in the file, which is the line we just wrote into the file.