Printing a pattern of input string in X shape

Question

Context:

Write a program to print the output for the given input(Example is given in comments of my code). String is of odd length.

I would be grateful if anyone could give feedback on my following code. The code runs correctly but I want to know if there can be any potential improvements in terms of code style and optimization.

 s=input("enter string") #take s="12345" for example #output should be: # 1 5 # 2 4 # 3 # 2 4 # 1 5 for i in range(0,len(s)): # loop runs 5 times from index 0 to index 4 if i==((len(s)-1)//2): #first condition prints the center of pattern print(" "*i,s[i]) #leading 2 spaces print 3 elif i>(len(s)-1)//2: # second condition prints the characters above the center 3 print(" "*(len(s)-1-i),s[len(s)-i-1]," "*(i-(len(s)-i)-1)+s[i]) # 1 5 # 2 4 # 3 else: print(" "*i,s[i]," "*(len(s)-(2*(i+1))-1)+s[len(s)-i-1]) # else statement prints characters below the center # in reversed order # 3 # 2 4 # 1 5 

Answer 1

Writing index-conditional statements on the inside of a loop is a code smell. Instead you should prefer "looping like a native" making appropriate use of enumerate and zip.

You can also replace the string-multiply approach with formatting widths:

def print_x(s: str) -> None: n = len(s) # Converging (top half) forward = s[:n//2] reverse = s[-1: (-1 - n)//2: -1] for i, (char1, char2) in enumerate(zip(forward, reverse)): print(f'{char1:>{i + 1}}{char2:>{n - 2*i - 1}}') # Middle, single-character case if n % 2 == 1: print(f'{s[n//2]:>{1 + n//2}}') # Diverging (bottom half) reverse = s[-n//2 - 1: -1 - n: -1] forward = s[(n + 1)//2:] for i, (char1, char2) in enumerate(zip(reverse, forward)): print(f'{char1:>{n//2 - i}}{char2:>{(n - 1)//2 + 2*i}}') 

Answer 2

A big change would be to improve the readability of the program.

Some changes I would make are:

• Add spacing between operators and make bracket style consistent (e.g. ((len(s)-1)//2) vs (len(s)-1)//2).
• Convert calculations that are done multiple times (e.g. mid and size) into variables.
• Break down the large print statements into smaller and more readable sections; just making the code more verbose.

input_string = input("Enter string: ") size = len(input_string) mid = size // 2 for i in range(size): if i == mid: print(' ' * i + input_string[i]) elif i > mid: left_space = ' ' * (size - 1 - i) middle_space = ' ' * (2 * i - size + 1) print(f"{left_space}{input_string[size-i-1]}{middle_space}{input_string[i]}") else: left_space = ' ' * i middle_space = ' ' * (size - 2 * i - 2) print(f"{left_space}{input_string[i]}{middle_space}{input_string[size-i-1]}")