Numpy.all() method is **“used to test whether all array elements along the mentioned axis evaluate to True.” **If you specify the parameter axis, it returns **True** if **all** elements are **True** for each axis.

**Syntax**

`numpy.all(array, axis = None, out = None, keepdims = <NoValue>)`

**Parameters**

The all() function takes up to four parameters.

**array**: This is the array on which we need to work.**axis**: Axis or axes around, which is a logical reduction of OR. The default (axis = None) executes logical OR overall input array dimensions. Axis may be negative, counted from the last axis to the first. If this is a tuple of ints, there is a reduction on multiple axes instead of a single or all axes.**out**: This is an optional field. Alternate output array to position the result into. It must have the same shape as the planned performance and maintain its form.**keepdims**: If this is**True**, the reduced axes are left in the result as dimensions with size one. With this option, the result will broadcast correctly against the input array.

**Return Value**

The np.all() method always returns a Boolean value. But this boolean value depends on the ‘**out**’ parameter.

Please note that Not a Number (NaN), positive infinity, and negative infinity are evaluated to **True** as they are not equal to zero.

**Example 1: How to Use numpy.all() Method**

```
import numpy as np
#Declaring different types of array
arr1 = [[True, False], [True, False]]
print(np.all(arr1, axis=0))
arr2 = [5, 10, 0, 100]
print(np.all(arr2))
print(np.all(np.nan))
arr3 = [[0, 0], [0, 0]]
print(np.all(arr3, axis=0))
```

**Output**

```
[ True False]
False
True
[False False]
```

**Example 2: Using the numpy all() method with a multidimensional array**

```
import numpy as np
# Create a 2D array
arr = np.array([[True, True], [True, True]])
# Use numpy.all() without specifying an axis
result = np.all(arr)
print(result)
```

**Output**

`True`

That’s it.

Ankit Lathiya is a Master of Computer Application by education and Android and Laravel Developer by profession and one of the authors of this blog. He is also expert in JavaScript and Python development.