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try...exceptThe _statement is used in Python to catch exceptions or run some error-prone code. Nowadays, every programming language has this feature, but in Python, it try...exceptis represented by these words and _keywords respectively. Besides try...except, another keyword, namely, finally_, can also be used with them.

Like forloops, these try, , catchand finallystatements can also be nested, and in this article, we will discuss that.

try...exceptNested statements in Python

As mentioned above, we can fornest these statements just like nested loops. See the following code for an example.

a = {"a": 5, "b": 25, "c": 125}

try:
    print(a["d"])
except KeyError:
    try:
        print("a:", a["a"])
    except:
        print("No value exists for keys 'a' and 'd'")
    finally:
        print("Nested finally")
finally:
    print("Finally")

Output:

a: 5
Nested finally
Finally

As we can see, the above program first initializes a dictionary with some key-value pairs and then tries to access dthe value for the key . Since no key-value pair exists, KeyErroran exception is raised and exceptcaught by the statement. The interpreter then tryruns the code under the nested block. Since a value exists for the key , it prints to the console and the code under the anested statement is executed . Finally, the code under the outer statement is executed.finallyfinally

This means that we can put try, , catchand finallystatements under any try, , catchand finallystatements. Let's understand this with an example. We will write some code that contains try, , catchand statements, all of which also have , , and statements below them.finallytrycatchfinally

a = {
    "a": 5,
    "b": 25,
    "c": 125,
    "e": 625,
    "f": 3125,
}

try:
    try:
        print("d:", a["d"])
    except:
        print("a:", a["a"])
    finally:
        print("First nested finally")
except KeyError:
    try:
        print("b:", a["b"])
    except:
        print("No value exists for keys 'b' and 'd'")
    finally:
        print("Second nested finally")
finally:
    try:
        print("c:", a["c"])
    except:
        print("No value exists for key 'c'")
    finally:
        print("Third nested finally")

Output:

a: 5
First nested finally
c: 125
Third nested finally

As we can see, first, the outer tryblock is executed. Since no value is found for the key , the code under the dnested statement will be executed and the nested will be executed. Since the outer block does not encounter any exception during execution, its block is skipped and the code under the outer block is executed.exceptfinallytryexceptfinally

We can even go a step further and create nnested try, , catchand finallystatements to the desired level. But as the number of nesting levels increases, the control flow or execution flow becomes a bit complex and difficult to manage. Navigating the try, , catchand finallystatements becomes challenging.