# How to put the max of 3 separate columns in a new column in python/pandas

for example we have: a b c 1 1 3 2 4 1 3 2 1 And now using python I’m trying to create this: a b c max 1 1 3 3c 2 4 1 4b 3 2 1 3a >Solution : If need match first maximal column join max converted to strings with… Read More How to put the max of 3 separate columns in a new column in python/pandas

# python – remove array column if it contains at least one 0

Let’s suppose I have a np.array like: array([[1., 1., 0., 1., 1.], [1., 1., 1., 1., 1.], [1., 1., 1., 1., 0.], [1., 1., 1., 1., 0.]]) I would like to know if there is a pythonic way to find all the columns that contain at least one occurence of 0. In the example I… Read More python – remove array column if it contains at least one 0

# How to get numpy to interpret object array slice as single array?

When you ask Numpy to make an array out of a collection including arbitrary objects, it will create an array of "object" type, which allows you to use index slicing across those objects, but since the object itself is unknown to numpy, you cannot index into the object in one go (even if that particular… Read More How to get numpy to interpret object array slice as single array?

# Why documentation etc. use @ in place of * for multiplication

Why many documentations and blog posts use @ in place of * (multiplication operator) in python. Here is an example. They use C@x instead of c*x (also found in the next lines in the page). Is @ used to say it is vector multiplication etc.? >Solution : They write it like that because the underlying… Read More Why documentation etc. use @ in place of * for multiplication

# Index of maximum value of each row of an array in Python

I have an array Pr. I want to print index of maximum value of each row. For example, for row 0, the maximum value is 1.72731864e+003 and it occurs at index 0. I present the expected output. import numpy as np Pr = np.array([[1.72731864e+003, 0.00000000e+000], [0.00000000e+000, 1.24439020e+003]]) MaxPr=Pr.max(axis=1) The expected output is indices=[0,1] >Solution :… Read More Index of maximum value of each row of an array in Python

# How to add noise to the first index in nump array

How to add noise to the first index of array,with the number of iterations the max number iteration is 2. I want to add a noise in range (1, max_iterator) to rows in order, for example: add 0.788 to row 1st add 1.233 to row 2nd add 0.788 to row 3rd add 1.233 to row… Read More How to add noise to the first index in nump array

# Pandas: how to compare a column to a column of lists

I have a dataframe with a column with many different-sized lists.I would like to compare it with a second column preferably without expending a column_of_lists to multiple columns. | value | column_of_lists | | — | — | | 1 | \[1,2,1,1\] | | 3 | \[3\] | | 1 | \[4,4\] | | 3… Read More Pandas: how to compare a column to a column of lists

# Locating indices with element 1 and converting to a list in Python

I have an array A. I want to identify all indices with element 1 and print as a list. But I am getting an error. I present the expected output. import numpy as np A=np.array([[1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0]]) A1=np.where(A==1) A1.tolist() print(A1) The error is in <module> A1.tolist()… Read More Locating indices with element 1 and converting to a list in Python

# Conditional operation between numpy array of different shapes

i have two numpy arrays of different shapes. import numpy data1 = numpy.array([[1, 2, 3, 4], [2, 6, 7, 8], [3, 10, 11, 12], [4, 13, 13, 12], [5, 10, 1, 12]]) data2 = numpy.array([[1, 2, 3, 4], [2, 6, 7, 8], [4, 13, 13, 12], [5, 10, 1, 12]]) I want to make an… Read More Conditional operation between numpy array of different shapes