# Python 2D Arrays: Two-Dimensional List Examples

Array is a data structure used to store elements. An array can only store similar types of elements. A Two Dimensional is defined as an Array inside the Array. The index of the array starts with 0 and ends with a size of array minus 1. We can create ‘n’ number of arrays in an array.

In the above image, we can see that an index uniquely identifies each array element.

## How to Create Array in Python?

We can create a two-dimensional array(list) with rows and columns.

Syntax:

```[[r1,r2,r3,..,rn],[c1,c2,c3,.......,cn]]
```

Where,

r stands for rows and c stands for columns

Example: Following is the example for creating

2D array with 4 rows and 5 columns

```array=[[23,45,43,23,45],[45,67,54,32,45],[89,90,87,65,44],[23,45,67,32,10]]
#display
print(array)
```

Output:

```[[23, 45, 43, 23, 45], [45, 67, 54, 32, 45], [89, 90, 87, 65, 44], [23, 45, 67, 32, 10]]
```

## Accessing the values

We can access the values using index position

Syntax:

We can get row value using `[]` operator

`array[row index]`

We can get column value using `[][]`

`Array[row index][column index]`

where,

• array is an input array
• row index is the row index position starts from 0
• column index is the column index position starts from 0 in a row.

Example:

In this example we are going to access the values using index positions

```#creare 2D array with 4 rows and 5 columns
array=[[23,45,43,23,45],[45,67,54,32,45],[89,90,87,65,44],[23,45,67,32,10]]

#display
print(array)

#get the first row
print(array[0])

#get the third row
print(array[2])

#get the first row third element
print(array[0][2])

#get the third row forth element
print(array[2][3])
```

Output:

```[[23, 45, 43, 23, 45], [45, 67, 54, 32, 45], [89, 90, 87, 65, 44], [23, 45, 67, 32, 10]]
[23, 45, 43, 23, 45]
[89, 90, 87, 65, 44]
43
65
```

We can also access elements using `for loop`

Syntax:

```for rows in the array:
for columns in rows:
print(columns)
```

where,

• rows are used to iterate the row by row
• columns is used to iterate the values present in each row.

Example:

```Creare 2D array with 4 rows and 5 columns
array=[[23,45,43,23,45],[45,67,54,32,45],[89,90,87,65,44],[23,45,67,32,10]]

#use for loop to iterate the array
for rows in array:
for columns in rows:
print(columns,end=" ")
print()
```

Output:

```23 45 43 23 45
45 67 54 32 45
89 90 87 65 44
23 45 67 32 10
```

## Inserting the values into the two-dimensional array

Here we are going to insert values into two dimensional array using insert() function

Syntax:

```array.insert(index,[values])
```

where,

• the array is the input array
• the index is the row position to insert a particular row
• value are the values to be inserted into the array

Example: Insert to values in the array

```#Create 2D array with 4 rows and 5 columns
array=[[23,45,43,23,45],[45,67,54,32,45],[89,90,87,65,44],[23,45,67,32,10]]

#insert the row at 5 th position
array.insert(2, [1,2,3,4,5])

#insert the row at 6 th position
array.insert(2, [1,2,3,4,5])

#insert the row at 7 th position
array.insert(2, [1,2,3,4,5])

#display
print(array)
```

Output:

```[[23, 45, 43, 23, 45], [45, 67, 54, 32, 45], [1, 2, 3, 4, 5], [1, 2, 3, 4, 5], [1, 2, 3, 4, 5], [89, 90, 87, 65, 44], [23, 45, 67, 32, 10]]
```

## Updating the values into the two-dimensional array

Here are two methods for updating values in the 2-D array(list).

You can update rows by using the following syntax

```array[row_index]= [values]
```

You can update column values inside rows by using the following syntax

```array[row_index][column_index]= [values]
```

Example:

```#creare 2D array with 4 rows and 5 columns
array=[[23,45,43,23,45],[45,67,54,32,45],[89,90,87,65,44],[23,45,67,32,10]]

#update row values in the 3rd row
array[2]=[0,3,5,6,7]

#update row values in the 5th row
array[2]=[0,3,5,6,7]

#update the first row , third column
array[0][2]=100

#update the second row , third column
array[1][2]=400

#display
print(array)
```

Output:

```[[23, 45, 100, 23, 45], [45, 67, 400, 32, 45], [0, 3, 5, 6, 7], [23, 45, 67, 32, 10]]
```

## Deleting the values from two-dimensional array

You can delete rows using the `del` function

Syntax:

```del array[index]
```

where,

• the array is the input array
• index refers to the row index

Example:

```#creare 2D array with 4 rows and 5 columns
array=[[23,45,43,23,45],[45,67,54,32,45],[89,90,87,65,44],[23,45,67,32,10]]

#delete row values in the 3rd row
del array[2]

#delete row values in the 2nd row
del array[1]

#display
print(array)
```

Output:

```[[23, 45, 43, 23, 45], [23, 45, 67, 32, 10]]
```

## Get the size of two-dimensional array

You can get the size of the two-dimensional array using the line() function. It will return the number of rows in the array

Syntax:

`len(array)`

Example:

Get the length of the two-dimensional array

```#creare 2D array with 4 rows and 5 columns
array=[[23,45,43,23,45],[45,67,54,32,45],[89,90,87,65,44],[23,45,67,32,10]]
#display
print(len(array))
```

Output:

`4`

## Summary

Here are some important Array(list) Methods

Method Description Syntax Example
Append(): This method helps us to add an element at the end to an existing array. array.append(value)
`# Adding an element using append method to the end of an array array=[1,2,3] array.append(4) print(array)`

Output:

`[1,2,3,4]`
Clear(): This method helps us to remove all the elements present in an array array.clear()
```# Removing all the elements from an array array=[1,2,3]
array.clear()```

Output:

`[]`
Copy(): This method helps us to copy the contents of an array to a new array array1=array.copy()
```#Copying the elements from an array to a new array array=[1,2,3] array1=[]
array1=array.copy()
print(array1)```

Output:

`[1,2,3]`
Count(): This method helps us to count the no.of occurences of a an specified element in an array array.count(element)
```#Counting the no of times an element is present in an array array=[1,2,3]
print(array.count(8))```
` Output: 0`
Extend(): This method helps us to extend an array beyond it’s consisting elements. array.extend(array1)
`#Extending an existing array with another array array=[1,2,3] array1=[4,5,6] array.extend(array1) print(array)`
`Output: [1,2,3,4,5,6]`
Index(): This method helps us to find the index of an element in an array array.index(element)
```#returing the index an element in an array array=[1,2,3]
print(array.index(3))```

Output:

`2`
Insert(): This method helps us to insert elements into an array at specified index. array.insert(index,element)
```#Inserting an element at a specified index into an array array=[1,2,3]
array.insert(2,4)
print(array)```

Output:

`[1,2,4,3]`
Pop(): This method helps us to remove an element at specified index array.pop(index)
```#Removing an element at specified index through pop method
array=[1,2,3]
array.pop(2)
print(array)```

Output:

`[1,2]`
Remove(): This method helps us to remove an particular matching element in an array. array.remove(element)
```array=[1,2,3]
array.remove(2)
print(array)```

Output:

`[1,3]`
Reverse(): This method helps is to reverse the elements in an array. array.reverse()
```array=[1,2,3,4]
array.reverse()
print(array)```

Output:

`[4,3,2,1]`