In python you can do string replace by method replace. It has several parameters:

  • old string − This is old substring to be replaced.
  • new string − This is the replacement of the old one.
  • limit − This is a limit and only the first N occurrences are replaced. It's optional.

Basic string replace in python

Giving only two parameters of string method is enough to replace all occurrences of a substring:

str = "Java is very nice language. Java is number 1"
print (str.replace("Java", "Python"))

result:

Python is very nice language. Python is number 1

String replace with limit

Replacing first N occurrences in string can be done by adding max parameter:

str = "Java is very nice language. Java is number 1"
print (str.replace("Java", "Python", 1))

result:

Python is very nice language. Java is number 1

Alternative string replace in python

Since python string are special and can be treated as sequences of characters you can do : string[:4]

string = "Java rulez!"
print(string[:4])
print(string[0:5] + "is boring")

result:

Java
Java is boring