Python: Make an iterator that drops elements from the iterable as soon as a condition is true
Python Itertools: Exercise-7 with Solution
Write a Python program to make an iterator that drops elements from the iterable as long as the elements are negative; afterwards, returns every element.
Sample Solution:
Python Code:
import itertools as it
def drop_while(nums):
return it.takewhile(lambda x : x < 0, nums)
nums = [-1,-2,-3,4,-10,2,0,5,12]
print("Original list: ",nums)
result = drop_while(nums)
print("Drop elements from the said list as long as the elements are negative\n",list(result))
#Alternate solution
def negative_num(x):
return x < 0
def drop_while(nums):
return it.dropwhile(negative_num, nums)
nums = [-1,-2,-3,4,-10,2,0,5,12]
print("Original list: ",nums)
result = drop_while(nums)
print("Drop elements from the said list as long as the elements are negative\n",list(result))
Sample Output:
Original list: [-1, -2, -3, 4, -10, 2, 0, 5, 12] Drop elements from the said list as long as the elements are negative [-1, -2, -3] Original list: [-1, -2, -3, 4, -10, 2, 0, 5, 12] Drop elements from the said list as long as the elements are negative [4, -10, 2, 0, 5, 12]
Python Code Editor:
Have another way to solve this solution? Contribute your code (and comments) through Disqus.
Previous: Write a Python program to make an iterator that drops elements from the iterable as soon as an element is a positive number.
Next: Write a Python program to create an iterator that returns consecutive keys and groups from an iterable.
What is the difficulty level of this exercise?
Test your Programming skills with w3resource's quiz.
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
- New Content published on w3resource:
- HTML-CSS Practical: Exercises, Practice, Solution
- Java Regular Expression: Exercises, Practice, Solution
- Scala Programming Exercises, Practice, Solution
- Python Itertools exercises
- Python Numpy exercises
- Python GeoPy Package exercises
- Python Pandas exercises
- Python nltk exercises
- Python BeautifulSoup exercises
- Form Template
- Composer - PHP Package Manager
- PHPUnit - PHP Testing
- Laravel - PHP Framework
- Angular - JavaScript Framework
- Vue - JavaScript Framework
- Jest - JavaScript Testing Framework