apply_discount_to_prices.py

# A sentence is a string of single-space separated words where each word can contain digits, lowercase letters, and the dollar sign
# '$'. A word represents a price if it is a sequence of digits preceded by a dollar sign.

# For example, "$100", "$23", and "$6" represent prices while "100", "$", and "$1e5" do not.
# You are given a string sentence representing a sentence and an integer discount. For each word representing a price, apply a 
# discount of discount% on the price and update the word in the sentence. All updated prices should be represented with exactly two decimal places.

# Return a string representing the modified sentence.

# Note that all prices will contain at most 10 digits.

 

# Example 1:

# Input: sentence = "there are $1 $2 and 5$ candies in the shop", discount = 50
# Output: "there are $0.50 $1.00 and 5$ candies in the shop"
# Explanation: 
# The words which represent prices are "$1" and "$2". 
# - A 50% discount on "$1" yields "$0.50", so "$1" is replaced by "$0.50".
# - A 50% discount on "$2" yields "$1". Since we need to have exactly 2 decimal places after a price, we replace "$2" with "$1.00".
# Example 2:

# Input: sentence = "1 2 $3 4 $5 $6 7 8$ $9 $10$", discount = 100
# Output: "1 2 $0.00 4 $0.00 $0.00 7 8$ $0.00 $10$"
# Explanation: 
# Applying a 100% discount on any price will result in 0.
# The words representing prices are "$3", "$5", "$6", and "$9".
# Each of them is replaced by "$0.00".


class Solution:
    def discountPrices(self, sentence: str, discount: int) -> str:
        words = sentence.split(' ')
        answer = ''
        for i in range(len(words)):
            if words[i][0] == '$':
                if words[i][1:len(words[i])].isdigit():
                    number = float(words[i][1:len(words[i])])
                    result = number - number * discount * .01
                    answer += "${:.2f}". format(result)
                else:
                    answer += words[i]
            else:
                answer += words[i]
            if i == len(words) - 1:
                continue
            else:
                answer += ' '
        
        return answer