Python not empty variable

Check if Variable is Empty in Python

First, we declared a variable named name and initialized it with None. We use the None keyword in Python to define a null value or no value. Remember, None is not the same as an empty string, a zero or False value, but it is a built-in constant in Python, a data type of its own, which is NoneType .

Then, we used the if statement with the not keyword, which is used to determine if the given variable is empty or not. This keyword inverts the value of an object. As an empty object is treated as False , we can use the not keyword to invert the object’s value and check whether it is empty.

Using is Operator

Use the is operator to check if the specified variable is empty in Python.

This code is similar to the previous one, but we used the is operator to check if the specified variable is None . In Python, None represents the absence of the value, which means a variable is not assigned any value yet. So, if the variable is set to None , the name is None expression will return True and result in executing the if block; otherwise, the else block.

Further reading:

How to check if Variable is None in Python

How to check if Variable exists in Python

Using Comparison Operators

Use == operator to check if the variable is empty in Python.

Use != operator to check if the variable is empty in Python.

For this section, we used two comparison operators: == represents equal to and != denotes not equal to. These operators can be used if we know the variable’s data type.

For example, in the above two code examples, we knew that the variable would be empty if it equals None . The second code snippet using the != operator is similar to the previous example using the == operator, but we exchanged the print statements to get desired results.

Using len() Method

Use the len() method to check if the specified variable is empty in Python.

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Check if the variable is empty or not in Python

In this tutorial, we will learn an easy yet important topic of how to check if the variable is empty or not in Python
The various sequences are:

Checking variable empty or not in Python

Now let’s first understand a little bit about these sequences.

LISTS – Check empty or not

• It is a data structure or data sequence in Python.
• Mutable in nature.
• Changeable in nature.
• Syntax to define a list is [ ].

TUPLES – check empty or not

• These are another type of data structure or data sequence.
• It’s immutable in nature.
• It’s irreversible which means no change can occur at any point.
• Syntax to define a list is ( ).

STRING – Check empty or not

• These are another type of data structure.
• It represents Unicode characters.
• [ ] can be used to access strings.

DICTIONARY – Check empty or not

• Dictionary is a random or unordered collection of data values.
• It has a key which is immutable in nature.
• Key should be unique also.
• Syntax to define a dictionary is .

NUMPY ARRAY – Check empty or not

• Numpy array is a grid of values.
• Values should be the same.
• Defined using numpy.array[].

Now let’s implement them using the python language.

NOTE: Any required explanation have been provided in code itself.

#Syntax to define a list l=[int(x) for x in input().split()] if len(l)==0: # len function to find the length of list print("The List is Empty") else: print("The list is not Empty")

-NO INPUT FROM USER SIDE- The List is Empty

#Syntax to define a String l=[x for x in input().split()] if len(l)==0: # len function to find the length of list print("The String is Empty") else: print("The String is not Empty")

-NO INPUT FROM USER SIDE- The String is Empty

#Syntax to define a list l=[int(x) for x in input().split()] a = tuple(l) #Convertig a list to tuple if len(l)==0: # len function to find the length of list print("The Tuple is Empty") else: print("The Tuple is not Empty")

-NO INPUT FROM USER SIDE- The Tuple is Empty.

#Syntax to define a list d= if(len(d)==0):#To find the length of dictionary print("Dictionary is Empty") else: print("Dictionary is not empty")

-NO INPUT FROM USER SIDE- Dictionary is Empty.

#Importing Numpy import numpy as np a = np.array([x for x in input().split()])#Syntax for defining Numpy Array if len(a)==0:#Len of Numpy Array print("Numpy array is empty") else: print("Numpy array is not empty")

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How to Properly Check if a Variable is Not Null in Python

To check if a Variable is not Null in Python, we can use 3 methods:

Note: Python programming uses None instead of null.

1. Check if the Variable is not null [Method 1]

The first method is using «is«, «not» and «None» keywords. Let’s see the syntax, Then the examples.

Syntax

Example 1: Check String Variable

The above program returns True if the variable is not null. If null, it returns False.

As you can see, in the output, the program returns True.

Example 2: Check None Variable

The program returned False because my_var is None (null).

Example 3: Check Empty Variable

We got True Because my_var is empty, not None

2. Check if the Variable is not null [Method 2]

The second method for checking if the variable is not null is using the != operator + None keyword.

Syntax

Example 1: Check String Variable

The third method is the if condition. This method returns False if the variable is None or empty.

Syntax

Example 1: Check String Variable

This tutorial taught us how to check if the variable is not null. For more variable articles, check out:

Related Tutorials:

Recent Tutorials:

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If a variable is empty Python | Example code

You can Use bool() to check if a variable is empty in Python. Or you can also use if not statement to check it.

How to check if a variable is empty in Python Example

Simple python example code. Print True if the variable has a non-empty value, and False otherwise. Empty values include empty sequences, the integer 0, and the None value.

var1 = '' var2 = <> var3 = [1, 2, 3] var4 = None print(bool(var1)) print(bool(var2)) print(bool(var3)) print(bool(var4)) 

Check empty variable with if not statement

bool is used implicitly when evaluating an object in a condition like an if or while statement, conditional expression, or a boolean operator.

Just use not keyword:

var1 = '' if not var1: print("Variable is empty") 

Output: Variable is empty

Do comment if you have any doubts and suggestions on this Python variable topic.

Note: IDE: PyCharm 2021.3.3 (Community Edition)

Windows 10

Python 3.10.1

All Python Examples are in Python 3, so Maybe its different from python 2 or upgraded versions.

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