在python中替换字符串中的字符

Question

I am trying to replace a character in a string using python. I am using a function called find_chr to find the location of the character that needs to be replaced.

def main():
    s='IS GOING GO'
    x='N'
    y='a'

    rep_chr(s,x,y)
def find_chr(s,char):
    i=0
    for ch in s:
        if ch==char:
            return (i)
            break        
        i+=1
    return -1
def rep_chr(s1,s2,s3):
    return print(s1==s1[0:find_chr(s1,s2)]+s3+s1[(find_chr(s1,s2)+1):])


main()

My problem is that instead of getting the new string, the function is returning 'False'. I would appreciate any pointer to get the replaced string.

Answer 1

change

return print(s1==s1[0:find_chr(s1,s2)]+s3+s1[(find_chr(s1,s2)+1):])

to

return s1[0:find_chr(s1,s2)]+s3+s1[(find_chr(s1,s2)+1):]

and print the result in your main :

print(rep_chr(s,x,y))

Answer 2

There is an inbuilt function:

string.replace(old, new, count)

this returns a modified copy

count is optional and is the number of times to replace - if it is set to 2 it will replace the first two occurrences.

string = 'abc abc abc def'
string.replace('abc','xyz',2)

returns

'xyz xyz abc def'

Answer 3

The problem is in your print statement inside rep_chr function.

s1==s1[0:find_chr(s1,s2)]+s3+s1[(find_chr(s1,s2)+1):]

The above statement means is s1 equal to s1[0:find_chr(s1,s2)]+s3+s1[(find_chr(s1,s2)+1):] ? which is false and that's why you are getting False as output.