# Solving 'Expected 2D Array, Got 1D Array Instead' Error

If you are a developer, you may have encountered the "Expected 2D array, got 1D array instead" error while working on a project. This error occurs when you are trying to pass a 1D array to a function that expects a 2D array. In this guide, we will provide you with a step-by-step solution to fix this error.

## What Causes the 'Expected 2D Array, Got 1D Array Instead' Error?

This error occurs when you are trying to pass a 1D array to a function that expects a 2D array. The function expects a 2D array with the shape `(n_samples, n_features)`, but you are passing a 1D array with the shape `(n_samples,)`.

## Step-by-Step Solution

Here's how you can fix the "Expected 2D array, got 1D array instead" error:

1.Import the necessary libraries:

``````import numpy as np
from sklearn import datasets
``````

``````iris = datasets.load_iris()
X = iris.data
y = iris.target
``````

3.Reshape the 1D array:

``````X = X.reshape(-1,1)
``````

4.Pass the 2D array to the function:

``````clf.fit(X, y)
``````

By following these steps, you should be able to fix the "Expected 2D array, got 1D array instead" error.

## FAQ

### Q1. What is a 2D array?

A 2D array is an array of arrays. It has two dimensions - rows and columns.

### Q2. What is a 1D array?

A 1D array is a single-dimensional array. It has only one dimension.

### Q3. What is the shape of a 2D array?

The shape of a 2D array is `(n_samples, n_features)`.

### Q4. What is the shape of a 1D array?

The shape of a 1D array is `(n_samples,)`.

### Q5. How do I reshape a 1D array?

You can reshape a 1D array using the `reshape()` method. For example, `X = X.reshape(-1,1)` reshapes `X` into a 2D array with one column.

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