# Python: Find the h-index, the largest positive number h such that h occurs in the sequence at least h times

## Python Programming Puzzles: Exercise-49 with Solution

Write a Python program to find the h-index, the largest positive number h such that h occurs in the sequence at least h times. If there is no such positive number return h = -1.

Input: [1, 2, 2, 3, 3, 4, 4, 4, 4] Output: 4 Input: [1, 2, 2, 3, 4, 5, 6] Output: 2 Input: [3, 1, 4, 17, 5, 17, 2, 1, 41, 32, 2, 5, 5, 5, 5] Output: 5

**Pictorial Presentation:**

**Sample Solution:**

**Python Code:**

```
#License: https://bit.ly/3oLErEI
def test(nums):
return max([-1] + [i for i in nums if i > 0 and nums.count(i) >= i])
nums = [1, 2, 2, 3, 3, 4, 4, 4, 4]
print("Original list of numbers:")
print(nums)
print("h-index, the largest positive number h such that h occurs in the said sequence at least h times:")
print(test(nums))
nums = [1,2,2,3,4,5,6]
print("\nOriginal list of numbers:")
print(nums)
print("h-index, the largest positive number h such that h occurs in the said sequence at least h times:")
print(test(nums))
nums = [3, 1, 4, 17, 5, 17, 2, 1, 41, 32, 2, 5, 5, 5, 5]
print("\nOriginal list of numbers:")
print(nums)
print("h-index, the largest positive number h such that h occurs in the said sequence at least h times:")
print(test(nums))
```

Sample Output:

Original list of numbers: [1, 2, 2, 3, 3, 4, 4, 4, 4] h-index, the largest positive number h such that h occurs in the said sequence at least h times: 4 Original list of numbers: [1, 2, 2, 3, 4, 5, 6] h-index, the largest positive number h such that h occurs in the said sequence at least h times: 2 Original list of numbers: [3, 1, 4, 17, 5, 17, 2, 1, 41, 32, 2, 5, 5, 5, 5] h-index, the largest positive number h such that h occurs in the said sequence at least h times: 5

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