Elements in array change data types from float to string

Question

When I append elements to a list that have the following format and type:

data.append([float, float, string])

Then stack the list using:

data = np.hstack(data)

And then finally reshape the array and transpose using:

data = np.reshape(data,(-1,3)).T

All the array elements in data are changed to strings. I want (and expected) the first and second columns in data to be of type float and the third of type string, but instead they are all of type string. [Interestingly, if I do not append the string elements to data and adjust the newshape to (-1,2), both columns are floats.] I cannot figure this one out. Any help would be appreciated.

I think as soon as numpy touches it it converts them to a common format unless told otherwise. I don't know if you can tell it dtypes with hstack, but here is an alternative: stackoverflow.com/questions/26018781/… — Markus
– Markus, Commented Oct 18, 2018 at 14:56
Markus, thanks for the help. Your comments guided me to this: stackoverflow.com/questions/42813011/… I was able to find a solution here using dtype=object. — Sebekemsaf
– Sebekemsaf, Commented Oct 18, 2018 at 18:24

Sebekemsaf · Accepted Answer · 2018-10-18 18:40:52Z

1

Because of the mix of numbers and strings, np.array will use the common format: string. The solution here is to convert data to type object which supports mixed element types. This is performed by using:

data = np.array(data, dtype=object)

prior to hstack.

answered Oct 18, 2018 at 18:40

Sebekemsaf

234 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Elements in array change data types from float to string

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related