Solve The Error “cannot cast array data from dtype(‘float64’) to dtype(‘

Python is a high-level programming language that is ideal for designing web applications and websites. It is always in demand as programmers all over the world are using Python for creating various applications that users are using but they are not obviously aware of the programming that is used to make that. Python is an easy-to-understand language and that’s the reason beginners are also trying various projects to learn it. Python has many libraries and frameworks that are designed for the convenience of programmers. NumPy, Numerical Python, is a Python library that is designed to easily work with arrays.

Array computing has become simpler with NumPy. When working with NumPy, you may experience “cannot cast array data from dtype(‘float64’) to dtype(‘<u32’) according to the rule ‘safe’”. You don’t need to worry when you face this error as we have the solutions to help you make the error go away. Let’s discuss how the error occurs

How the error shows up

When you try to use (a,b.t) where a and b are numpy.ndarray type along with version 1.11.0, you may end up with the following error warning

TypeError: Cannot cast array data from dtype('float64') 
               to dtype('S32') according to the rule 'safe'

Solutions To Tackle the Error “cannot cast array data from dtype(‘float64’) to dtype(‘<u32’) according to the rule ‘safe’”

The cause of the error is the use of a string in the ‘dtype(‘float64’)’. As the error says, the ‘dtype(‘<u32) needs float, and ‘dtype(‘float64’)’ is a string, which returns the error message. Check out the options to solve the error

Option 1 – Change string to float

The error can be fixed if you change the string to float. According to Warren Weckesser  and BrenBarn, you can use the following code to convert string to float

a = map(lambda x: float(x),a)
b = map(lambda x: float(x),b),b.T)

Alternatively, you can use the below code

a = map(float,a)
b = map(float,b),b.T)

Option 2 – Convert the whole numpy array to float

This is another way to get rid of the error. You can simply convert the whole array into a float to fix the issue. You can take the reference from the below code

train = train.astype(float)
train_target = train_target.astype(float)

Using a similar approach to your code can help you resolve the error warning.


And that’s exactly how you can tackle the error warning “cannot cast array data from dtype(‘float64’) to dtype(‘<u32’) according to the rule ‘safe’”. The solution is quite simpler as you just need to convert string to float.

I hope you find it helpful! I wish you luck!

Feel free to drop us a message if you need further assistance!

Leave a Reply

Your email address will not be published. Required fields are marked *