Below is the solution on leetcode by someone. But I need help understanding what they have done. First, the : in def romanToInt(self, s: str). What is : doing here? Is it like an = sign?
Second: How do i get this code to work in VS code, so I can test if it works. I cannot work out how to get it to run. There is no print statement, or function call in the example.
I’ve edited your code for readability. When you enter a code block into a forum post, please precede it with a separate line of three backticks and follow it with a separate line of three backticks to make it easier to read.
You can also use the “preformatted text” tool in the editor (</>) to add backticks around text.
Like the -> int on the same line, it is an annotation. It is kind of like a comment for the function.
In this case, the s parameter value is supposed to be a string or that the input to the function should be a string. The part after the : is just a text string and could be anything.
The -> int is expressing that the return value of the function is an integer.
Keep in mind these are just comments and not actual type declarations (like TypeScript in JavaScript).
Think of it as a short-hand version of:
def romanToInt(self, s: str) -> int: # s parameter is asString, function returns an integer
Using normal comments clutters up the line. Using the annotation is more concise.
The : in def romanToInt(self, s: str) -> int: is part of the function definition in Python. The : is used to indicate the start of a code block and the function definition is followed by a colon.
In this code, def romanToInt(self, s: str) -> int: is a method definition for the class Solution. The method takes two arguments: self and s. The self argument is a reference to the instance of the class and s is a string representing a Roman numeral. The str in s: str is a type hint indicating that s is a string. The -> int part is a return type hint indicating that the method returns an integer.
To test this code in Visual Studio Code, you will need to create a new file with the following code:
class Solution:
def romanToInt(self, s: str) -> int:
roman_to_integer = {
'I': 1,
'V': 5,
'X': 10,
'L': 50,
'C': 100,
'D': 500,
'M': 1000,
}
s = s.replace("IV", "IIII").replace("IX", "VIIII").replace("XL", "XXXX").replace("XC", "LXXXX").replace("CD", "CCCC").replace("CM", "DCCCC")
return sum(map(lambda x: roman_to_integer[x], s))
if __name__ == '__main__':
sol = Solution()
s = 'XXI'
result = sol.romanToInt(s)
print(result)
#! /usr/bin/env python3
roman = {
'I':1, 'V':5, 'X':10, 'L':50, 'C':100, 'D':500, 'M':1000
}
def convert(rn):
converted = []
for val in rn:
if val in roman.keys():
converted.append(roman[val])
return sum(converted)
print(convert('MXXVI'))
