Why do the following code samples:

```
np.array([[1, 2], [2, 3, 4]])
```

```
np.array([1.2, "abc"], dtype=float)
```

…all give the following error?

ValueError: setting an array element with a sequence.

## Solution

#### Possible reason 1: trying to create a jagged array

You may be creating an array from a list that isn’t shaped like a multi-dimensional array:

```
numpy.array([[1, 2], [2, 3, 4]]) # wrong!
```

```
numpy.array([[1, 2], [2, [3, 4]]]) # wrong!
```

In these examples, the argument to `numpy.array`

contains sequences of different lengths. Those will yield this error message because the input list is not shaped like a "box" that can be turned into a multidimensional array.

#### Possible reason 2: providing elements of incompatible types

For example, providing a string as an element in an array of type `float`

:

```
numpy.array([1.2, "abc"], dtype=float) # wrong!
```

If you really want to have a NumPy array containing both strings and floats, you could use the dtype `object`

, which allows the array to hold arbitrary Python objects:

```
numpy.array([1.2, "abc"], dtype=object)
```

Source: StackOverflow.com