String Repetition and spacing in List - Python

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We are given a list of strings and our task is to modify it by repeating or adding spaces between elements based on specific conditions. For example, given the list `a = ['hello', 'world', 'python']`, if we repeat each string twice, the output will be `['hellohello', 'worldworld', 'pythonpython'].

Using List Comprehension

List comprehension allows us to modify each element in the list efficiently. We can repeat each string a fixed number of times or add spaces dynamically.

# Repeat each string twice 
a = ["hello", "world", "python"] 
a = [x * 2 for x in a] 

print(a)

['hellohello', 'worldworld', 'pythonpython']

Explanation:

• This method efficiently repeats each string using `x * 2`, which duplicates each element.
• It is useful when we want to repeat each string a fixed number of times.

Let's explore some more ways and see how we can perform string repetition and spacing in list.

Using join() for Spacing

We can use the join() method to combine list elements with a specific spacing between them.

# Join list elements with 3 spaces in between 
a = ["hello", "world", "python"] 
res = "   ".join(a) 

print(res)

hello   world   python

Explanation:

• The join() method efficiently inserts spaces between elements.
• This is useful when formatting strings with specific spacing.

Using for Loop

Using a for loop, we can manually repeat elements or add spaces dynamically based on conditions.

# Repeat each string twice and add a space between repetitions 
a = ["hello", "world", "python"] 
b = [] 

for x in a: 
    b.append((x + " ") * 2) 

print(b)

['hello hello ', 'world world ', 'python python ']

Explanation:

• This method provides more control over repetition and spacing.
• However, it is less efficient due to the use of a loop and repeated append operations.

Using map() with Lambda Function

map() function allows us to apply modifications to each element without using an explicit loop.

# Repeat each string three times with a space in between 
a = ["hello", "world", "python"] 
a = list(map(lambda x: (x + " ") * 3, a)) 

print(a)

['hello hello hello ', 'world world world ', 'python python python ']

Explanation: map() function applies a transformation to each element.