Given a String “str” in Java, the task is to convert this string to float type.
Examples:
Input: str = "1.0" Output: 1.0 Input: str = "3.14" Output: 3.14
Approach 1: (Naive Method)
One method is to traverse the string and add the numbers one by one to the float type. This method is not an efficient approach.
Approach 2: (Using Float.parseFloat() method)
The simplest way to do so is using parseFloat() method of Float class in java.lang package. This method takes the string to be parsed and returns the float type from it. If not convertible, this method throws error.
Syntax:
Float.parseFloat(str);
Below is the implementation of the above approach:
Example 1: To show successful conversion
// Java Program to convert string to float class GFG { // Function to convert String to Float public static float convertStringToFloat(String str) { // Convert string to float // using parseFloat() method return Float.parseFloat(str); } // Driver code public static void main(String[] args) { // The string value String stringValue = "1.0"; // The expected float value float floatValue; // Convert string to float floatValue = convertStringToFloat(stringValue); // Print the expected float value System.out.println( stringValue + " after converting into float = " + floatValue); }} |
1.0 after converting into float = 1.0
Example 2: To show unsuccessful conversion
// Java Program to convert string to float class GFG { // Function to convert String to Float public static void convertStringToFloat(String str) { float floatValue; try { // Convert string to float // using parseFloat() method floatValue = Float.parseFloat(str); // Print the expected float value System.out.println( str + " after converting into float = " + floatValue); } catch (Exception e) { // Print the error System.out.println( str + " cannot be converted to float: " + e.getMessage()); } } // Driver code public static void main(String[] args) { // The string value String str1 = ""; String str2 = null; String str3 = "GFG"; // Convert string to float // using parseFloat() method convertStringToFloat(str1); convertStringToFloat(str2); convertStringToFloat(str3); }} |
cannot be converted to float: empty String null cannot be converted to float: null GFG cannot be converted to float: For input string: "GFG"
Approach 3: (Using Float.valueOf() method)
The valueOf() method of Float class converts data from its internal form into human-readable form.
Syntax:
Float.valueOf(str);
Below is the implementation of the above approach:
Example 1: To show successful conversion
// Java Program to convert string to float class GFG { // Function to convert String to Float public static float convertStringToFloat(String str) { // Convert string to float // using valueOf() method return Float.valueOf(str); } // Driver code public static void main(String[] args) { // The string value String stringValue = "1.0"; // The expected float value float floatValue; // Convert string to float floatValue = convertStringToFloat(stringValue); // Print the expected float value System.out.println( stringValue + " after converting into float = " + floatValue); }} |
1.0 after converting into float = 1.0
