FREE PCEP Variable Scope and the `global` keyword Questions and Answers

Question 1

What is the output of the following code?

```python
var = 100

def my_func():
    var = 50
    print(var)

my_func()
print(var)
```

Accepted Answer

50
100

Answer

Inside `my_func`, `var = 50` creates a new local variable named `var` that shadows the global variable. This local variable is printed (50). The global variable `var` remains unchanged, so the final `print(var)` statement prints its original value (100).

Question 2

What is the output of this code snippet?

```python
var = 100

def my_func():
    global var
    var = 50

my_func()
print(var)
```

Accepted Answer

50

Answer

The `global var` statement tells Python that within this function, `var` refers to the globally scoped variable. Therefore, the assignment `var = 50` modifies the global variable, not a local one. The final print statement outputs the new value of the global variable.

Question 3

What is the scope of a variable defined inside a function, without using the `global` keyword?

Accepted Answer

Local scope

Answer

A variable that is created (assigned a value) inside a function is local to that function. It can only be accessed from within that function and is destroyed when the function finishes executing.

Question 4

What is the output of the following code?

```python
value = 1

def change_value():
    print(value)

change_value()
```

Accepted Answer

1

Answer

Functions can read or access global variables without needing the `global` keyword. The `global` keyword is only required when you need to modify or assign a new value to the global variable from within the function.

Question 5

What happens when this code is executed?

```python
def my_func():
    global new_var
    new_var = 'Hello'

my_func()
print(new_var)
```

Accepted Answer

The code prints 'Hello'.

Answer

If you use the `global` keyword for a variable that does not yet exist in the global scope, Python will create that variable in the global scope when it is assigned a value inside the function. Therefore, `new_var` becomes a global variable accessible after the function call.

(PCEP) Certified Entry-Level Python Programmer Practice Test

(PCEP) Certified Entry-Level Python Programmer Practice Test

FREE PCEP Variable Scope and the `global` keyword Questions and Answers