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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Python: Tips of the Day
Find current directory and file's directory:
To get the full path to the directory a Python file is contained in, write this in that file:
import os dir_path = os.path.dirname(os.path.realpath(__file__))
(Note that the incantation above won't work if you've already used os.chdir() to change your current working directory, since the value of the __file__ constant is relative to the current working directory and is not changed by an os.chdir() call.)
To get the current working directory use
import os cwd = os.getcwd()
Documentation references for the modules, constants and functions used above:
- The os and os.path modules.
- The __file__ constant
- os.path.realpath(path) (returns "the canonical path of the specified filename, eliminating any symbolic links encountered in the path")
- os.path.dirname(path) (returns "the directory name of pathname path")
- os.getcwd() (returns "a string representing the current working directory")
- os.chdir(path) ("change the current working directory to path")
Ref: https://bit.ly/3fy0R6m
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