如果满足特定条件，则从多个列表中删除一个元素

Question

I would like to remove an element from a list if it obeys a certain if condition.

In this particular case I would like to remove an element from multiple lists called EPSILON_I, X_COORDINATE and Z_COORDINATE, if the element in the same position in another list, C_I, is smaller than 0.001.

Any ideas how I can do this? I currently have the following code but it fails with the error: 'TypeError: list indices must be integers or slices, not float'. I am open to any code that works..

for i,j,k,l in zip(X_COORDINATE, Z_COORDINATE, C_I, EPSILON_I) :
if k < 0.001 :
    del EPSILON_I[l]
    del X_COORDINATE[i]
    del Z_COORDINATE[j]
else :
    pass 

Answer 1

You can use enumerate to get the index for the elements you are considering.

for idx, (i,j,k,l) in enumerate(zip(X_COORDINATE, Z_COORDINATE, C_I, EPSILON_I)):

Answer 2

I think this code should work for you:

j=0
for i in range(len(C_I)):
    if C_I[i] < 0.001:
        del EPSILON_I[j]
        del X_COORDINATE[j]
        del Z_COORDINATE[j]
    else:
        j +=1

You need to use different indexes j and i so it doesn't jump a value when it removes an element.

If you execute it with:

C_I=[1,0.0001,1,0.0001,1]

EPSILON_I=['a','b','c','d','e']
X_COORDINATE=['a','b','c','d','e']
Z_COORDINATE=['a','b','c','d','e']

You get:

In[7]: EPSILON_I
Out[7]: ['a', 'c', 'e']

I'd recommend you to use capitalized variables only for constants as PEP8 standard recommends.