Python Program that Extract words starting with Vowel From A list

Given a list with string elements, the following program extracts those elements which start with vowels(a, e, i, o, u).

Input : test_list = [“all”, “love”, “get”, “educated”, “by”, “gfg”] 
Output : [‘all’, ‘educated’] 
Explanation : a, e are vowels, hence words extracted.
Input : test_list = [“all”, “love”, “get”, “educated”, “by”, “agfg”] 
Output : [‘all’, ‘educated’, ‘agfg’] 
Explanation : a, e, a are vowels, hence words extracted. 

Method 1 : Using startswith() and loop

In this, we check for each word and check if it starts with a vowel using startswith() on the first alphabet of every word. The iteration part is done using the loop.

Python3

# initializing list
test_list = ["all", "love", "and", "get", "educated", "by", "gfg"]

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

res = []
vow = "aeiou"
for sub in test_list:
    flag = False

    # checking for begin char
    for ele in vow:
        if sub.startswith(ele):
            flag = True
            break
    if flag:
        res.append(sub)

# printing result
print("The extracted words : " + str(res))

Output

The original list is : ['all', 'love', 'and', 'get', 'educated', 'by', 'gfg']
The extracted words : ['all', 'and', 'educated']

Time Complexity: O(N)

Auxiliary Space: O(N)

Method 2 : Using any(), startswith() and loop

In this, we check for vowels using any(), and rest all the functionality is similar to the above method.

Python3

# initializing list
test_list = ["all", "love", "and", "get", "educated", "by", "gfg"]

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

res = []
vow = "aeiou"
for sub in test_list:

    # check for vowel beginning
    flag = any(sub.startswith(ele) for ele in vow)

    if flag:
        res.append(sub)

# printing result
print("The extracted words : " + str(res))

Output

The original list is : ['all', 'love', 'and', 'get', 'educated', 'by', 'gfg']
The extracted words : ['all', 'and', 'educated']

Time Complexity: O(n²)
Auxiliary Space: O(n)

Method 3 : Using find() method

Python3

#Starting with vowels
# initializing list
test_list = ["all", "love", "and", "get", "educated", "by", "gfg"]

# printing original list
print("The original list is : " + str(test_list))
def vowelstart(s):
    if(s[0]=="a" or s[0]=="e" or s[0]=="i" or s[0]=="o" or s[0]=="u"):
        return True
    return False
res = []

for sub in test_list:
    if(vowelstart(sub)):
        res.append(sub)
# printing result
print("The extracted words : " + str(res))

Output

The original list is : ['all', 'love', 'and', 'get', 'educated', 'by', 'gfg']
The extracted words : ['all', 'and', 'educated']

Time Complexity: O(N)

Auxiliary Space: O(N)

Method 4 : Using for loop

Python3

# Python Program that Extract words starting
# with Vowel From A list initializing list
test_list = ["all", "love", "and", "get", "educated", "by", "gfg"]

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

res = []
vow = "aeiou"
for i in test_list:
    if i[0] in vow:
        res.append(i)

# Printing result
print("The extracted words : " + str(res))

Output

The original list is : ['all', 'love', 'and', 'get', 'educated', 'by', 'gfg']
The extracted words : ['all', 'and', 'educated']

Time Complexity: O(N)

Auxiliary Space: O(N)

Method #5: Using filter(),list(),lambda functions and dictionary

Python3

# Starting with vowels
# initializing list
test_list = ["all", "love", "and", "get", "educated", "by", "gfg"]

vowels = {
    "a": 0, "e": 0, "i": 0, "o": 0, "u": 0}
# printing original list
print("The original list is : " + str(test_list))


res = list(filter(lambda x: x[0] in vowels.keys(), test_list))


# printing result
print("The extracted words : " + str(res))

Output

The original list is : ['all', 'love', 'and', 'get', 'educated', 'by', 'gfg']
The extracted words : ['all', 'and', 'educated']

Time Complexity: O(N)
Auxiliary Space: O(N)

Method #6: Using operator.countOf() method

Python3

# Python Program that Extract words starting
# with Vowel From A list initializing list
import operator as op
test_list = ["all", "love", "and", "get", "educated", "by", "gfg"]

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

res = []
vow = "aeiou"
for i in test_list:
    if op.countOf(vow, i[0]) > 0:
        res.append(i)

# Printing result
print("The extracted words : " + str(res))

Output

The original list is : ['all', 'love', 'and', 'get', 'educated', 'by', 'gfg']
The extracted words : ['all', 'and', 'educated']

Time Complexity: O(N)
Auxiliary Space : O(N)

Method#7: Using regular expression

Python3

import re

# initializing list
test_list = ["all", "love", "and", "get", "educated", "by", "gfg"]

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

vow = "aeiou"
res = [x for x in test_list if re.match(f"^[{vow}]", x)]

# printing result
print("The extracted words : " + str(res))
#This code is contributed by Vinay Pinjala.

Output

The original list is : ['all', 'love', 'and', 'get', 'educated', 'by', 'gfg']
The extracted words : ['all', 'and', 'educated']

Time Complexity: O(N)
Auxiliary Space : O(N)

Method#8: Using list comprehension and ‘in’

Here’s another approach using a list comprehension and checking if the first character is a vowel using in operator:

Python3

test_list = ["all", "love", "and", "get", "educated", "by", "gfg"]

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

res = [word for word in test_list if word[0] in "aeiou"]

# Printing result
print("The extracted words : " + str(res))

Output

The original list is : ['all', 'love', 'and', 'get', 'educated', 'by', 'gfg']
The extracted words : ['all', 'and', 'educated']

Time Complexity: O(N)

Auxiliary Space: O(N)