IndexError：列出索引超出范围，如果

Question

i am extremely new to Python. I have some code in R that I am trying to rewrite in Python and I've come across an issue that I can't seem to find an answer to - apologies if this has already been answered or the answer is obvious, I have searched and can't fix my issue.

I have a list 'height' which is a column of 481 numbers from a spreadsheet. I wish to use hrc, a list from the min to the max values of height, of the same length as the height list, but all values equally spaced. For each value in hrc i want to run it through the following code, but i get Indexerror: list index out of range.

hrc = np.linspace(min(height),max(height),len(height))
Qrc = []
for i in range(0,len(hrc)): 
  if(hrc[i]<0.685): 
      Qrc.append(30.69*((hrc[i]-0.156)**1.115))
  elif(0.685<=hrc[i] and hrc[i]<1.917):
      Qrc.append(27.884*((hrc[i]-0.028)**1.462))
  elif(1.917<=hrc[i]):
      Qrc.append(30.127*((hrc[i]-0.153)**1.502))

I appreciate any help!

Answer 1

Do not index into lists (if you do not have to) - iterate over its values.

Check your if conditions, you can simplify them - if a lower range would have fit, the next range does not need to check if the value now is bigger as the lower range (if it was, you wouldnt be checking that one now):

import numpy as np
height = [i/100.0 for i in range(0,200,20)]
hrc = np.linspace(min(height),max(height),len(height))

Qrc = []
for value in hrc: 
    if value < 0.685 : 
        Qrc.append(30.69*((value-0.156)**1.115))
    elif value < 1.917 :
        Qrc.append(27.884*((value-0.028)**1.462))
    else:
        Qrc.append(30.127*((value-0.153)**1.502))

print(len(height))  # 10
print(len(hrc))     # 10

print(hrc)   
print(Qrc)   

Output:

[0.  0.2 0.4 0.6 0.8 1.  1.2 1.4 1.6 1.8]
[nan, 0.942858721586344, 6.367024848753282, 12.411632276269644, 
 19.100800437337597, 26.749961012743743, 35.16634580199501, 
 44.275837504844475, 54.021755132798525, 64.35896171368269]