Python 2D Lists Flashcard

Front

How do you access the element in the second row and third column of a 2D list `matrix`? Options: `matrix[1][2]`, `matrix[2][3]`, `matrix[2][1]`, `matrix[3][2]`

Back

`matrix[1][2]`

Front

How can you modify the value of the first element in the first row of a 2D list `matrix` to 5? Options: `matrix[0][0] = 5`, `matrix[1][1] = 5`, `matrix[0] = 5`, `matrix = 5`

Back

`matrix[0][0] = 5`

Front

What will be the output of the following code snippet if `matrix = [[1, 2], [3, 4]]`?
```python
print(matrix[1][1])
```

Back

`4`

Front

Which of the following is a valid 2D list in Python? Options: `[[1, 2, 3], [4, 5], [6]]`, `[[1, 2], 3, [4, 5]]`, `[[1], [2, 3], 4]`, `[[1] [2] [3]]`

Back

`[[1, 2, 3], [4, 5], [6]]`

Front

How can you add a new row `[5, 6, 7]` to an existing 2D list `matrix`? Options: `matrix.append(5, 6, 7)`, `matrix.append([5, 6, 7])`, `matrix += [5, 6, 7]`, `matrix.insert(len(matrix), [5, 6, 7])`

Back

`matrix.append([5, 6, 7])`

Front

What error is raised when trying to access an element in a 2D list with an index that is out of range?

Back

IndexError

Front

How do you remove the last row from a 2D list `matrix`? Options: matrix[-1].delete(), `matrix.pop()`, `matrix.remove(-1)`, Both A) and B) are correct

Back

`matrix.pop()`

Front

What is the result of the following code snippet?
```python
matrix = [[1, 2], [3, 4]]
for row in matrix:
for item in row:
print(item, end=' ')
```

Back

`1 2 3 4`

Front

What is the correct way to find the number of rows in a 2D list `matrix`? Options: `len(matrix[0])`, `len(matrix)`, `len(matrix.columns)`, `len(matrix.rows)`

Back

`len(matrix)`

Front

Which of the following is true about 2D lists in Python?
Options:
All rows must have the same number of columns.
2D lists can only contain integer values.
2D lists are implemented using arrays in Python.
2D lists can contain rows of different lengths.

Back

2D lists can contain rows of different lengths.