Python program to extract Keywords from a list

Given a List of strings, extract all the words that are keywords.

Input : test_list = [“Gfg is True”, “Its a global win”, “try Gfg”], 
Output : [‘is’, ‘True’, ‘global’, ‘try’] 
Explanation : All strings in result list is valid Python keyword.

Input : test_list = [“try Gfg”], 
Output : [‘try’] 
Explanation : try is used in try/except block, hence a keyword. 

Method #1 : Using iskeyword() + split() + loop

This is one of the ways in which this task can be performed. In this, we check for keyword using iskeyword() and convert a string to words using split(). The logic of extension to all strings happens using loop.

Python3

# Python3 code to demonstrate working of
# Extract Keywords from String List

# Using iskeyword() + loop + split()
import keyword

# initializing list
test_list = ["Gfg is True", "Gfg will yield a return",
             "Its a global win", "try Gfg"]

# printing original list
print("The original list is : " + str(test_list))


# iterating using loop
res = []
for sub in test_list:
   for word in sub.split():

       # check for keyword using iskeyword()
       if keyword.iskeyword(word):
           res.append(word)

# printing result
print("Extracted Keywords : " + str(res))

Output:

The original list is : [‘Gfg is True’, ‘Gfg will yield a return’, ‘Its a global win’, ‘try Gfg’] Extracted Keywords : [‘is’, ‘True’, ‘yield’, ‘return’, ‘global’, ‘try’]

Time Complexity: O(n²)

Auxiliary Space: O(n)

Method #2: Using list comprehension

This is yet another way in which this task can be performed. Similar to the above method but much compact on paper, use similar functionalities as the above method.

Python3

# Python3 code to demonstrate working of
# Extract Keywords from String List

# Using list comprehension
import keyword

# initializing list
test_list = ["Gfg is True", "Gfg will yield a return",
             "Its a global win", "try Gfg"]

# printing original list
print("The original list is : " + str(test_list))

# One-liner using list comprehension
res = [ele for sub in test_list for ele in sub.split() if keyword.iskeyword(ele)]

# printing result
print("Extracted Keywords : " + str(res))

Output:

The original list is : [‘Gfg is True’, ‘Gfg will yield a return’, ‘Its a global win’, ‘try Gfg’] Extracted Keywords : [‘is’, ‘True’, ‘yield’, ‘return’, ‘global’, ‘try’]

Time Complexity: O(n²)

Auxiliary Space: O(n)