Convert Snake Case string to Camel Case in Java - GeeksforGeeks

01 Aug, 2020
Given a string in Snake Case, the task is to write a Java program to convert the given string from snake case to camel case and print the modified string.
Examples:
Input: str = “geeks_for_geeks”Output: GeeksForGeeks
Input: str = “snake_case_to_camel_case”Output: SnakeCaseToCamelCase
The idea is to first capitalize the first letter of the string.Then convert the string to string builder.Then traverse the string character by character from the first index to the last index and check if the character is underscored then delete the character and capitalize the next character of the underscore.Print the modified string.
The idea is to first capitalize the first letter of the string.
Then convert the string to string builder.
Then traverse the string character by character from the first index to the last index and check if the character is underscored then delete the character and capitalize the next character of the underscore.
Print the modified string.
Below is the implementation of the above approach:
Java
// Java program for the above approach  import java.io.*;  class GFG {      // Function to convert snake case    // to camel case    public static String    snakeToCamel(String str)    {        // Capitalize first letter of string        str = str.substring(0, 1).toUpperCase()              + str.substring(1);          // Convert to StringBuilder        StringBuilder builder            = new StringBuilder(str);          // Traverse the string character by        // character and remove underscore        // and capitalize next letter        for (int i = 0; i < builder.length(); i++) {              // Check char is underscore            if (builder.charAt(i) == '_') {                  builder.deleteCharAt(i);                builder.replace(                    i, i + 1,                    String.valueOf(                        Character.toUpperCase(                            builder.charAt(i))));            }        }          // Return in String type        return builder.toString();    }      // Driver Code    public static void        main(String[] args)    {          // Given String        String str = "geeks_for_geeks";          // Function Call        str = snakeToCamel(str);          // Modified String        System.out.println(str);    }}
GeeksForGeeks

Method 2: Using String.replaceFirst() method
The idea is to use String.replaceFirst() method to convert the given string from snake case to camel case.First, capitalize the first letter of the string.Run a loop till the string contains underscore (_).Replace the first occurrence of a letter that present after the underscore to the capitalized form of the next letter of the underscore.Print the modified string.
The idea is to use String.replaceFirst() method to convert the given string from snake case to camel case.
First, capitalize the first letter of the string.
Run a loop till the string contains underscore (_).
Replace the first occurrence of a letter that present after the underscore to the capitalized form of the next letter of the underscore.
Print the modified string.
Below is the implementation of the above approach:
Java
// Java program for the above approach  class GFG {      // Function to convert the string    // from snake case to camel case    public static String    snakeToCamel(String str)    {        // Capitalize first letter of string        str = str.substring(0, 1).toUpperCase()              + str.substring(1);          // Run a loop till string        // string contains underscore        while (str.contains("_")) {              // Replace the first occurrence            // of letter that present after            // the underscore, to capitalize            // form of next letter of underscore            str = str                      .replaceFirst(                          "_[a-z]",                          String.valueOf(                              Character.toUpperCase(                                  str.charAt(                                      str.indexOf("_") + 1))));        }          // Return string        return str;    }      // Driver Code    public static void    main(String args[])    {        // Given string        String str = "geeks_for_geeks";          // Print the modified string        System.out.print(snakeToCamel(str));    }}
GeeksForGeeks

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