# NumPy Input and Output: binary_repr() function

## numpy.binary_repr() function

The binary_repr() function is used to get the binary representation of the input number as a string.

For negative numbers, if width is not given, a minus sign is added to the front.
If width is given, the two’s complement of the number is returned, with respect to that width.

In a two's-complement system negative numbers are represented by the two's complement of the absolute value.
This is the most common method of representing signed integers on computers [R16].
A N-bit two's-complement system can represent every integer in the range -2^{N-1} to +2^{N-1}-1.

Syntax:

`numpy.binary_repr(num, width=None)`

Version: 1.15.0

Parameter:

Name Description Required /
Optional
num Only an integer decimal number can be used.
int
Required

Returns: bin : str

Binary representation of num or two's complement of num.

Notes:

binary_repr is equivalent to using base_repr with base 2, but about 25x faster.

NumPy.binary_repr() method Example-1:

``````>>> import numpy as np
>>> np.binary_repr(5)
``````

Output:

```'101'
```

NumPy.binary_repr() method Example-2:

``````>>> import numpy as np
>>> np.binary_repr(-5)
``````

Output:

```'-101'
```

NumPy.binary_repr() method Example-3:

``````>>> import numpy as np
>>> np.binary_repr(5, width=4)
``````

Output:

```'0101'
```

The two's complement is returned when the input number is negative and width is specified:

``````>>> import numpy as np
>>> np.binary_repr(-2, width=3)
``````

Output:

```'110'
```
``````>>> import numpy as np
>>> np.binary_repr(-2, width=5)
``````

Output:

```'11110'
```

Python - NumPy Code Editor:

Previous: printoptions() function
Next: base_repr() function

﻿