Update and rename transpose_matrix.md to transpose.md

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Angelos Chalaris
2019-10-08 09:53:08 +03:00
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---
title: transpose
tags: list,intermediate
---
Returns the transpose of a two-dimensional list.
Use `*lst` to get the passed list as tuples.
Use `zip()` in combination with `list()` to create the transpose of the given two-dimensional list.
```py
def transpose(lst):
return list(zip(*lst))
```
```py
transpose([[1, 2, 3], [4, 5, 6], [7, 8, 9], [10, 11, 12]]) # [(1, 4, 7, 10), (2, 5, 8, 11), (3, 6, 9, 12)]
```

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---
title: transpose_matrix
tags: matrix,list,zip,intermediate
---
Obtaining the transpose of a matrix making use of `zip()` function.
Python `zip()` function takes the iterable elements as input and returns the iterator.
Since zip funtion returns a `zip object`, we can cast it as list wit `list()`.
```py
list(zip([1,2,3],['a','b','c'], [True, False, True])) # [(1, 'a', True), (2, 'b', False), (3, 'c', True)]
```
Using `*list`, we can access to each element of the list
```py
[[1, 2, 3], [4, 5, 6], [7, 8, 9], [10, 11, 12]] # [[1, 2, 3], [4, 5, 6], [7, 8, 9], [10, 11, 12]]
*[[1, 2, 3], [4, 5, 6], [7, 8, 9], [10, 11, 12]] # [1, 2, 3] [4, 5, 6] [7, 8, 9] [10, 11, 12]
```
Combining these two elements we can transpose a matrix. We can access to each row of the matrix using the operator `*` to use them as args of `zip()` function.
```py
def transpose_matrix(l:list):
return list(zip(*l))
```
```py
print(transpose_matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9], [10, 11, 12]])) # [(1, 4, 7, 10), (2, 5, 8, 11), (3, 6, 9, 12)]
```