如何在 python 中使用替换 function

Question

I'm trying to make a function that takes a string from the user and replaces a word in the string with another using the replace function. I'm new to using the replace function but I have this so far.

def replacer(phrase, *args):
    # Sample:
    # replacer('hello world', ('l', 'r')) --> 'herro worrd'
    outputString = ""
    for char in phrase:
        foundFlag = False
        for arg in args:
            if char == arg:
                outputString += arg[1]
                foundFlag = True
                break
        if foundFlag:
            outputString += char
    return outputString

Answer 1

You don't need to write a custom function for replacing chars in a string python string object has a builtin method called replace() .

string.replace(s, old, new[, maxreplace])

It returns a copy of a string with all occurrence of sub string old replaced by new.

for eg:-

string = 'hello world'
new_string = string.replace('l','r', 2)
output==>  herro world

Answer 2

You seem to have mixed up your logic. You are comparing each character with the tuple passed, and you only append to the outputString if the condition matches. Make the following changes:

Change

if char == arg:

to

if char == arg[0]:

and

if foundFlag:

to

if not foundFlag:

It will then print:

herro worrd

Answer 3

from dataclasses import replace


letter = '''Dear <|NAME|>
            you are selected
            Date:<|DATE|> 
'''

name = input("Enter your name\n")
date = input("Enter today's date\n")
letter = letter.replace('<|NAME|>',name)
letter = letter.replace('<|DATE|>',date)
print(letter)