# NumPy - vstack() function

The NumPy vstack() function stacks arrays in sequence vertically (row wise). This is equivalent to concatenation along the first axis after 1-D arrays of shape (N,) have been reshaped to (1,N).

### Syntax

```numpy.vstack(tup)
```

### Parameters

 `tup` `Required. `Specify sequence of ndarrays to be vertically stacked. The arrays must have the same shape along all but the first axis. 1-D arrays must have the same length.

### Return Value

Returns the array formed by stacking the given arrays.

### Example:

In the example below, vstack() function is used to stack two given arrays.

```import numpy as np

Arr1 = np.array([[10,20],[30, 40]])
Arr2 = np.array([[50,60],[70, 80]])

#stacking arrays vertically
Arr3 = np.vstack((Arr1, Arr2))

#displaying results
print("Arr1 is:")
print(Arr1)
print("\nArr2 is:")
print(Arr2)
print("\nArr3 is:")
print(Arr3)
```

The output of the above code will be:

```Arr1 is:
[[10 20]
[30 40]]

Arr2 is:
[[50 60]
[70 80]]

Arr3 is:
[[10 20]
[30 40]
[50 60]
[70 80]]
```

### Example:

Consider one more example, where two arrays has same shape along all except different first axis.

```import numpy as np

Arr1 = np.array([10, 20, 30])
Arr2 = np.array([[40,50,60],[70,80,90]])

#stacking arrays vertically
Arr3 = np.vstack((Arr1, Arr2))

#displaying results
print("Arr1 is:")
print(Arr1)
print("\nArr2 is:")
print(Arr2)
print("\nArr3 is:")
print(Arr3)
```

The output of the above code will be:

```Arr1 is:
[10 20 30]

Arr2 is:
[[40 50 60]
[70 80 90]]

Arr3 is:
[[10 20 30]
[40 50 60]
[70 80 90]]
```

❮ NumPy - Array Manipulation

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