How to replace a value in array in numpy python

Question

I have a very basic question in numpy arrays:

My array looks something like this:

Array = [["id1", "1.0"],["id2", "0.0"]] 

I want to read the second element of the array and replace with an another character. Its like

for i in range(0,len(array)):
 if array[i] == "0.0":
 array[i] = "ClassA"
 else
 array[i] = "ClassB"

How to achieve this. I am not able to read "0.0" or "1.0" correctly. Please help.

• hiro protagonist: why the numpy tag? these are not numpy arrays.
• Doubt Dhanabalu: @hiroprotagonist - I am sorry if that is the case, the element type is numpy.ndarray. Is this and the numpy arrays are different? And checked for the dtype of the element - it is "str18912".
• Prakash Palnati: ["id1" "1.0"] don't they have comma between them??
• Doubt Dhanabalu: @PrakashPalnati - Thank you for pointing me out the mistake. I have updated the question.

Answer 1

You have two arrays inside an array. The below code should work:

array = [["id1", "1.0"],["id2", "0.0"]]
for item in array:
 if item[1] == "0.0":
 item[1] = "ClassA"
 else:
 item[1] = "ClassB"

Answer 2

you are missing ,s in the definition of your array. your array is the same as this: [["id11.0"], ["id20.0"]] (strings just get concatenated). if your arrays are numpy arrays then this is the way they are represented (printed). but that does not work as input...

starting from your code you could to this:

array = [["id1", "1.0"], ["id2", "0.0"]]
for i, (id_, number) in enumerate(array):
 if number == "0.0":
 array[i] = [id_, "ClassA"]
 else:
 array[i] = [id_, "ClassB"]

or, more elegant, use a list-comprehension:

array = [[id_, "ClassA"] if number == "0.0" else [id_, "ClassB"] 
 for id_, number in array ]

• Doubt Dhanabalu: Protagnoistn - Thank you very much for the response. This also has worked for me.