Python / Numpy AttributeError: 'float' object has no attribute 'sin'

python pandas numpy floating-point attributeerror

This fails for the same reason as:

import numpy as nparr = np.array([1.0, 2.0, 3.0], dtype=object)np.sin(arr)# AttributeError: 'float' object has no attribute 'sin'

When np.sin is called on an object array, it tries to call the sin method of each element.

If you know the dtype of θr.values, you can fix this with:

arr = np.array(θr.values).astype(np.float64)  # assuming the type is float64np.sin(arr)  # ok!

python pandas numpy floating-point attributeerror

Quick fix if you know the possible data types of θr:

xr = xw + L*np.sin(θr.astype(float))

Better solution. Get the data type right from the beginning when creating the dataframe.

Instead of:

self.data = pd.DataFrame(index=range(n), columns=columns)...data.iloc[i, :] = new_data_dict

(Which I was using)

Use:

data = pd.DataFrame(index=range(n), columns=columns, dtype=float)

or:

data = pd.DataFrame(data=np.empty((n, len(columns)), columns=columns)

or:

data = pd.DataFrame(np.full((n, len(columns), np.nan), columns=columns)

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