How to rewrite the value of a certain element in a nested list in python? -

  m = [[3.5, 1.0, 9.2, 4.0], [0, 0, 0, 0], [3.0, 1.0, 8.0, -2.0]] c_idx = 2 for count 4 in category 4: for count5 for category (lane (count4)): if m [count4] Index (M [count4] [Count5]) == c_idx: M [count4] = m [count4] [: c_idx] + [0] + m [count4] [c_idx + 1:] count4 + = 1 count5 + = 1 Print (m)  

So I want to rewrite the element of a certain position for the list, M but it shows me an error:

  If M [count4] Index (M [count4] [count5]) == c_idx: index error: out of range index index  

The result should be:

  [ [3.5, 1.0, 0, 4.0], [0, 0, 0, 0], [3.0, 1.0, 0, -2.0]]  

I do not know where I was wrong I'll help people!

just type count4 + = 1 and [0, 0, 0, [3.0, 1.0, 8.0, -> count5 + = 1

  m = [[3.5, 1.0, 9.2, 4.0], [0, 0, 0, 0] 2.0]] for c_idx = 2 limit (in the count4): in the count5 for the category (lane (count4)): If M [count4]. Index (M [count4] [count5]) == c_idx: m [count4] = m [count4] [: c_idx] + [0] + m [count4] [c_idx + 1:] print (m) [[3.5, 1.0, 0, 4.0], [0, 0, 0, 0], [3.0, 1.0, 0, -2.0]]  

for / loop Category Already + = 1 For you however, there are many cleaner outlines mentioned in the other answer.