Just out of curiosity. It doesn’t seem very logical that typeof NaN is number. Just like NaN === NaN or NaN == NaN returning false, by the way. Is this one of the peculiarities of javascript, or would there be a reason for this? Edit: thanks for your answers. It’s not an easy thing to … Read more
Suppose I have a DataFrame with some NaNs: >>> import pandas as pd >>> df = pd.DataFrame([[1, 2, 3], [4, None, None], [None, None, 9]]) >>> df 0 1 2 0 1 2 3 1 4 NaN NaN 2 NaN NaN 9 What I need to do is replace every NaN with the first non-NaN … Read more
Given a pandas dataframe containing possible NaN values scattered here and there: Question: How do I determine which columns contain NaN values? In particular, can I get a list of the column names containing NaNs? 14 Answers 14
I have a DataFrame with many missing values in columns which I wish to groupby: import pandas as pd import numpy as np df = pd.DataFrame({‘a’: [‘1’, ‘2’, ‘3’], ‘b’: [‘4’, np.NaN, ‘6’]}) In [4]: df.groupby(‘b’).groups Out[4]: {‘4’: [0], ‘6’: [2]} see that Pandas has dropped the rows with NaN target values. (I want to … Read more
Is it possible to set an element of an array to NaN in Python? Additionally, is it possible to set a variable to +/- infinity? If so, is there any function to check whether a number is infinity or not? 5 Answers 5
I’ve got a pandas DataFrame filled mostly with real numbers, but there is a few nan values in it as well. How can I replace the nans with averages of columns where they are? This question is very similar to this one: numpy array: replace nan values with average of columns but, unfortunately, the solution … Read more
I have a dataframe with ~300K rows and ~40 columns. I want to find out if any rows contain null values – and put these ‘null’-rows into a separate dataframe so that I could explore them easily. I can create a mask explicitly: mask = False for col in df.columns: mask = mask | df[col].isnull() … Read more
I have a double in Java and I want to check if it is NaN. What is the best way to do this? 7 Answers 7
I want to figure out how to remove nan values from my array. My array looks something like this: x = [1400, 1500, 1600, nan, nan, nan ,1700] #Not in this exact configuration How can I remove the nan values from x? 12 Answers 12
Why do comparisons of NaN values behave differently from all other values? That is, all comparisons with the operators ==, <=, >=, <, > where one or both values is NaN returns false, contrary to the behaviour of all other values. I suppose this simplifies numerical computations in some way, but I couldn’t find an … Read more
