python 程序中的问题，我们从给定字符串中获取一个字符串，并将所有第一个字符替换为“$”符号

Question

This is the full question: Write a Python program to get a string from a given string where all occurrences of its first char have been changed to '$', except the first char itself. Sample String: 'restart' Expected Result: 'resta$t'

The code I gave was as follows:

e="Test string"
f=""
for k in range(0,len(e)):  
    if(str[k]==e[0]):
        f+="$"
    else:
        f+=e[k]
print("New string: ",f)

The error I got back was in this line: if(str[k]==e[0]): The error shown was TypeError: 'type' object is not subscriptable I made an observation that if I replaced the variable e with str, I get the result without issues. Does this mean I can only run this code using str as a variable, or is there an alternate solution?

Answer 1

This works like you want, I think:

e = "test String"
f = e[0]
for char in e[1:]:
    if char == e[0]:
        f+="$"
    else:
        f+=char

print(f)

#  tes$ S$ring

Though I have a suspicion there must be some more pythonic way

Answer 2

I have implemented your question in a easy way.

e="restart"
x=e[0]
e1=e.replace(x,'$')
e2=x+e1[1::]
print(e2)

Answer 3

quote="If you cannot make it good, at least make it look good."
quoteList = list(quote)
for i in range(len(quoteList)):
  quoteList[0] = "$"
  if quoteList[i] == " ":
    quoteList[i+1] = "$"
"".join(quoteList)