How to get a shape of a list in Python? A list in Python doesnâ€™t have a specific shape or size, as it can be dynamically changed by adding or removing elements. However, you can determine the length of a list using the built-in len() function. You can use the shape of a list to refer the number of elements in each dimension of the list. If a list is one-dimensional, then its shape is simply the number of elements in the list. If a list is multi-dimensional, its shape is a tuple of the number of elements in each dimension.

You can get a list shape in Python using many ways, for example, by using `len()`

, and `numpy.shape()`

methods. In this article, I will explain how to get the shape of the list by using all these methods with examples.

## 1. Quick Examples ofÂ Getting List Shape

If you are in a hurry, below are some quick examples of getting list shape.

```
# Quick examples ofÂ getting list shape
# Example 1: Get list shape in Python
mylist = [2, 4, 6, 8]
result = len(mylist)
# Example 2: Get the shape of a list
# Using len() function
mylist = [[2, 4, 6], [1, 3, 5], [7, 8, 9]]
num_rows = len(mylist)
num_columns = len(mylist[0])
# Example 3: Get the shape of a nested list
num_rows = len(mylist)
num_columns = len(mylist[0])
for i in range(num_rows):
if len(mylist[i]) != num_columns:
raise ValueError("Nested lists must have the same length")
# Example 4: Get the shape of a one-dimensional list
# Using numpy.shape() method
mylist = [1, 3, 6, 9, 2]
result = np.shape(mylist)
# Example 5: Get the shape of the list
# Using numpy.shape() method
mylist = [[2, 4, 6], [1, 3, 5], [7, 8, 9]]
result = np.shape(mylist)
# Example 6: Using numpy.shape() method
arr = np.array(mylist)
shape = arr.shape
```

## 2. Get the Shape of a One-Dimensional List in Python

You can get the shape of a one-dimensional list in Python, using the len() function. This function returns the number of elements in the list, which corresponds to the size of the one-dimensional list. For example, apply this function over the given list `mylist`

, it will return the integer(4) which is equal to the number of elements present in a list. This is the shape of the list because it is one-dimensional.

```
# Get shape of the list using len()
mylist = [2, 4, 6, 8]
print("List:", mylist)
result = len(mylist)
print("Shape of the list is : ", result)
```

Yields below output.

## 3. Get the Shape of a 2-Dimensional Python List

You can use the `len()`

function to get the number of rows and the length of each row(number of columns), which gives you the shape of the 2-D list. This program first gets the number of rows in the list using `len(mylist)`

. Then it gets the length of the first row using `len(mylist[0])`

.

This function gets the shape of a list that can be extended to higher-dimensional lists as well, with each call to `len()`

get the length of the list along a different dimension.

```
# Initialize the list
mylist = [[2, 4, 6], [1, 3, 5], [7, 8, 9]]
print("Original list: ", mylist)
# Get the shape of a list
# Using len() function
num_rows = len(mylist)
num_columns = len(mylist[0])
print("Get the shape of rows: ", num_rows)
print("Get the shape of a columns: ", num_columns)
```

Yields below output.

You can also get the shape of a nested list, using the `len()`

function. First, you can use this function to get the number of rows and columns of a given nested list. Then, you can use a for loop over each nested list and check if it has the same length as the first nested list. If any nested list has a different length, you raise a `ValueError`

.

```
# Initialize the list
mylist = [[2, 4, 6], [1, 3, 5], [7, 8, 9]]
print("Original list: ", mylist)
num_rows = len(mylist)
num_columns = len(mylist[0])
# Get the shape of a nested list
for i in range(num_rows):
if len(mylist[i]) != num_columns:
raise ValueError("Nested lists must have the same length")
print("Get the shape of a rows: ", num_rows)
print("Get the shape of a columns: ", num_columns)
```

Yields the same output as above.

## 4. Get the Shape of a List Using numpy.shape() Method

Alternatively, you can use the `numpy.shape()`

from the Numpy module of Python to get the shape of a list. This function returns a tuple of integers representing the shape of the list. In the below example, I will provide a 2D list called `mylist`

with `3`

rows and `3`

columns and then uses the `numpy.shape()`

method to get the shape of the list as a tuple of integers.

```
import numpy as np
# Initialize the list
mylist = [[2, 4, 6], [1, 3, 5], [7, 8, 9]]
print("Original list: ", mylist)
# Get the shape of list
# Using numpy.shape() method
result = np.shape(mylist)
print("Shape of list is : ", result)
# Output:
# Original list: [[2, 4, 6], [1, 3, 5], [7, 8, 9]]
# Shape of list is : (3, 3)
```

Following the below example, first, you can convert the list into a NumPy array using the `np.array()`

function. Then you can use the `shape`

the attribute of the NumPy array to get the shape of the array as a tuple of integers. Finally, you can access the tupleâ€™s elements to get the listâ€™s number of rows and columns.

```
# Using numpy.shape() method
arr = np.array(mylist)
shape = arr.shape
print("Shape of list is : ", shape)
```

Yields the same output as above.

## 5. Conclusion

In this article, I have explained how to get the shape of the list of one-dimensional and two-dimensional in Python by using `len()`

, and `numpy.shape()`

methods with examples. And also we have learned the shape of a 1-D list is the length of the list and the shape of a 2-D list is the number of rows and columns of the list.

Happy Learning !!

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