Python - 如何检查列表中的下几个元素是否符合某些语句

Question

I have a huge list of values, and I want to search for pattern: if listItem == some value and next 10 items in list meet some statement, then do something. How to do this to avoid long multiple if condition code like that?

for i in range (0, len(list)):
    if list[i] == someValue and list[i+1] !=someValue and list[i+2] !=someValue and [...] and list[i+10] !=someValue: 
        doSomething()

Answer 1

You can do it like this:

for i in range(len(lst)):
    if lst[i] == someValue and all(x != someValue for x in lst[i+1:i+11]): 
        doSomething()

I changed the variable name from list to lst because you shopuld not overwrite the list builtin type and I also removed the 0 in the range fucntion as it is not needed.

The all fucntion checks that every element in the iterable passed as argument evaluates to True , and our iterable is a sequence of bools with the next 10 elements checked against someValue .

Another option would be using enumerate(...) to avoid having to get the value again from the list instead of range(len(...)) :

for i, value in enumerate(lst):
    if value == someValue and all(x != someValue for x in lst[i+1:i+11]): 
        doSomething()

And we could make it into a generator:

for i in (i for i, value in enumerate(lst) if value == someValue and all(x != someValue for x in lst[i+1:i+11])):
    doSomething()

@HeapOverflow suggested another way to check for that condition which is more readable (see his answer for further detail and drop a like) that conbined with the generator syntax would be:

for i in (i for i, value in enumerate(lst) if value == someValue not in lst[i+1:i+11]):
    doSomething()

Answer 2

Using membership test and chaining :

for i, value in enumerate(lst):
    if value == someValue not in lst[i+1:i+11]:
        doSomething()

Answer 3

Did you mean that you are searching for arbitrary values?

target = [someValue1, someValue2, ... someValue11]
for i in range (len(lst) - 10):
    if lst[i:i+11] == target: 
        doSomething()

Answer 4

Try this:

for i in range (0, len(list)):
    if list[i] == someValue and all(x != someValue for x in list[i+1:i+10]): 
        doSomething()