PYTHON

how many nan in array python

np.count_nonzero(~np.isnan(data))

numpy find rows containing nan

# in each case returns array of bool
np.isnan(a).any(axis=1) # rows where any value is nan
np.isnan(a).all(axis=1) # rows where all values are nan

python numpy array check if all nans

np.all(np.isnan(numpy_array))

python test if value is np.nan

import numpy as np

mynan = np.nan
mynum = 18

print("NaN? : ", np.isnan(mynan)) # Use np.isnan() to test
print("NaN? : ", np.isnan(mynum))

# Results:
# Nan? : True
# NaN? : False

check nan values in a np array

array_has_nan = np.isnan(array_sum)

Check np.nan value

import pandas as pd
import numpy as np

df = pd.DataFrame(
	[[np.nan, 72, 67],
	[23, 78, 62],
	[32, 74, np.nan],
	[np.nan, 54, 76]],
	columns=['a', 'b', 'c'])

value = df.at[0, 'a']  #nan
isNaN = np.isnan(value)
print("Is value at df[0, 'a'] NaN :", isNaN)

value = df.at[0, 'b']  #72
isNaN = np.isnan(value)
print("Is value at df[0, 'b'] NaN :", isNaN)