Great! Naturally, when an exception is thrown, we can do more than just print a custom error message. Consider this example:
while True:
try:
x = int(input('Provide a number: '))
break
except ValueError:
print('That is not a number! Try again. ')
In the example above, we ask the user to provide a number using the input() function within a while True loop. input() provides a string from the user, so we want to convert it to a number using int(). Python Documentation states that int() throws a ValueError exception if the argument can't be converted to an integer.
In our case, two options are possible:
int() converts user input successfully, the next line of code is executed, which is break: we escape the otherwise infinite while loop.int() fails and throws a ValueError, the try block is immediately interrupted. Then, break is never executed. Instead, the except block prints an error message, and the whole loop repeats in another iteration.Inside a loop, keep asking the user to provide a filename until it's a valid one and the file can be read.
When the filename is incorrect, print:
Could not read the file. Try another one.
When the filename is correct, simply print its contents.
You can test the correctness of the program for the animals.txt.
Use a while True loop, as shown in the example. Use a try-except block, and catch any IOError.
