CODEWITHSUNDEEP
python
LJ101
LJ101

Reputation: 29

How do I start at index 1 in my list and end just before the last element in the list

enter code here   count = 0
                  for i in range(1,len(listOfmountains)-1):
                      if listOfmountains[i+1] > listOfmountains[i]:
                      count +=1
                   elif listOfmountains[i-1] > listOfmountains[i]:
                         count +=1
                   return count
enter code hereif __name__ == "__main__":

testcase = [1000,1250,1200,1300,1100,1500,1400]
print("{} is the number of peaks in {}".format(countPeaks(testcase),testcase))

testcase = [1000,1250,2000,1600,2100]
print("{} is the number of peaks in {}".format(countPeaks(testcase),testcase))
testcase =  [2000, 1250, 3500, 1600, 1400, 1650, 1800, 850, 1775, 1900]
print("{} is the number of peaks in {}".format(countPeaks(testcase), testcase))

I want to start at 1 and end at the number before the last number. I am iterating through a list. I am trying to see the number of peaks not counting the first number and last number by the way.

Upvotes: 0

Views: 60

Answers (2)

gmdev
gmdev

Reputation: 3155

You were nearly there, you just need to change range(1, len(listOfMountains)) to range(1, len(listOfMountains)-1.

The method signature for range() is as follows:

range(start, stop, step)

range() will create a range that includes the start value and excludes the stop value. For example:

print([i for i in range(0,4)])

will only print the values: [0,1,2,3] (note that it excludes the stop value).

Upvotes: 1

Raiyan Chowdhury
Raiyan Chowdhury

Reputation: 311

Just substract 1 from the upper bound of the range function:

count = 0
for i in range(1,len(listOfmountains)-1):
    if listOfmountains[i+1] > listOfmountains[i]:
         count +=1
    elif listOfmountains[i-1] > listOfmountains[i]:
         count +=1
return count

Upvotes: 0

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