Python Beginner Exercise 5: Generate new list by removing unwanted object

• also post at dev
  

  Question

  Given:

  str_list = ["Emma", "Jon", "", "Kelly", None, "Eric", ""]

  Expected Output:

  
  Original list of sting
  ['Emma', 'Jon', '', 'Kelly', None, 'Eric', '']

After removing empty strings
['Emma', 'Jon', 'Kelly', 'Eric']

## My solution
I don't have any clue at first, so I look at the hint and it tell me to use filter() function, or use the for loop and if condition to remove the empty strings from a list

### I Search and Learn The filter() Function

```python
str_list = ["Emma", "Jon", "", "Kelly", None, "Eric", ""]  
print("Original list of sting")

filtered_list = list(filter(None, str_list))  
print("After removing empty strings")  
print(filtered_list)

• filter() function has a syntax of filter(function, iterable) and return a iterator, so I cannot just print out the result, need to use a list to include all the element.
• However I feel using list comprehension is faster, easier and more Pythonic than the filter function,

Or Use List Comprehension

str_list = ["Emma", "Jon", "", "Kelly", None, "Eric", ""]  
new_list = [x for x in str_list if x]  

print(new_list)

Other solution

• Using if loop

  str_list = ["Emma", "Jon", "", "Kelly", None, "Eric", ""]
  res_list = []
  for s in str_list:
  # check for non empty string
  if s:
      res_list.append(s)
  print(res_list)

  algo of the loop:
  create an new empty
  then iterate the old list
  check the object's truth is false
  (empty string and None are considered False in default)
  if the object is True add to new list

  My reflection

• I cannot figure out how to use the if loop at first, as i don't remember the default truth value of an object.

Credit

• exercise form Pynative