How to split a string in C/C++, Python and Java?

Difficulty Level : Easy
Last Updated : 22 Jul, 2021

Splitting a string by some delimiter is a very common task. For example, we have a comma-separated list of items from a file and we want individual items in an array.
Almost all programming languages, provide a function split a string by some delimiter.

In C:

// Splits str[] according to given delimiters.
// and returns next token. It needs to be called
// in a loop to get all tokens. It returns NULL
// when there are no more tokens.
char * strtok(char str[], const char *delims);

C

// A C/C++ program for splitting a string
// using strtok()
#include <stdio.h>
#include <string.h>
 
int main()
{
    char str[] = "Geeks-for-Geeks";
 
    // Returns first token
    char *token = strtok(str, "-");
   
    // Keep printing tokens while one of the
    // delimiters present in str[].
    while (token != NULL)
    {
        printf("%s\n", token);
        token = strtok(NULL, "-");
    }
 
    return 0;
}

Output: Geeks
    for
    Geeks

In C++

Note:  The main disadvantage of strtok() is that it only works for C style strings.
       Therefore we need to explicitly convert C++ string into a char array.
       Many programmers are unaware that C++ has two additional APIs which are more elegant
       and works with C++ string.

Method 1: Using stringstream API of C++

Prerequisite: stringstream API

Stringstream object can be initialized using a string object, it automatically tokenizes strings on space char. Just like “cin” stream stringstream allows you to read a string as a stream of words.

Some of the Most Common used functions of StringStream.
clear() — flushes the stream 
str() —  converts a stream of words into a C++ string object.
operator << — pushes a string object into the stream.
operator >> — extracts a word from the stream.

The code below demonstrates it.

C++

#include <bits/stdc++.h>
using namespace std;
 
// A quick way to split strings separated via spaces.
void simple_tokenizer(string s)
{
    stringstream ss(s);
    string word;
    while (ss >> word) {
        cout << word << endl;
    }
}
 
int main(int argc, char const* argv[])
{
    string a = "How do you do!";
    // Takes only space separated C++ strings.
    simple_tokenizer(a);
    cout << endl;
    return 0;
}

Output : How 
     do 
     you
     do!

Method 2: Using C++ find() and substr() APIs.

Prerequisite: find function and substr().

This method is more robust and can parse a string with any delimiter, not just spaces(though the default behavior is to separate on spaces.) The logic is pretty simple to understand from the code below.

C++

#include <bits/stdc++.h>
using namespace std;
 
void tokenize(string s, string del = " ")
{
    int start = 0;
    int end = s.find(del);
    while (end != -1) {
        cout << s.substr(start, end - start) << endl;
        start = end + del.size();
        end = s.find(del, start);
    }
    cout << s.substr(start, end - start);
}
int main(int argc, char const* argv[])
{
    // Takes C++ string with any separator
    string a = "Hi$%do$%you$%do$%!";
    tokenize(a, "$%");
    cout << endl;
 
    return 0;
}

Output: Hi 
    do 
    you
    do
    !

Method 3: Using temporary string

If you are given that the length of the delimiter is 1, then you can simply use a temp string to split the string. This will save the function overhead time in the case of method 2.

C++

#include <iostream>
using namespace std;
 
void split(string str, char del){
    // declaring temp string to store the curr "word" upto del
      string temp = "";
   
      for(int i=0; i<(int)str.size(); i++){
        // If cur char is not del, then append it to the cur "word", otherwise
          // you have completed the word, print it, and start a new word.
         if(str[i] != del){
            temp += str[i];
        }
          else{
            cout << temp << " ";
              temp = "";
        }
    }
       
      cout << temp;
}
 
int main() {
 
    string str = "geeks_for_geeks";    // string to be split
     char del = '_';    // delimiter around which string is to be split
   
      split(str, del);
     
    return 0;
}

Output

geeks for geeks

In Java :
In Java, split() is a method in String class.

// expregexp is the delimiting regular expression; 
// limit is the number of returned strings
public String[] split(String regexp, int limit);

// We can call split() without limit also
public String[] split(String regexp)

Java

// A Java program for splitting a string
// using split()
import java.io.*;
public class Test
{
    public static void main(String args[])
    {
        String Str = new String("Geeks-for-Geeks");
 
        // Split above string in at-most two strings 
        for (String val: Str.split("-", 2))
            System.out.println(val);
 
        System.out.println("");
   
        // Splits Str into all possible tokens
        for (String val: Str.split("-"))
            System.out.println(val);
    }
}

Output:

Geeks
for-Geeks

Geeks
for
Geeks

In Python:
The split() method in Python returns a list of strings after breaking the given string by the specified separator.

 
  // regexp is the delimiting regular expression; 
  // limit is limit the number of splits to be made 
  str.split(regexp = "", limit = string.count(str))

Python

line = "Geek1 \nGeek2 \nGeek3";
print line.split()
print line.split(' ', 1)

Output:

['Geek1', 'Geek2', 'Geek3']
['Geek1', '\nGeek2 \nGeek3']

This article is contributed by Aditya Chatterjee. If you like GeeksforGeeks and would like to contribute, you can also write an article and mail your article to review-team@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
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