To convert a
Python Class
Object to
JSON String, or save the parameters of the class
object to a
JSON String, use
json.
Syntax – json.dumps()
- json is the module.
- dumps is the method that converts the python object to JSON string.
- myobject is the Python Class object and myobject.
2.JSON Print Print from File using Python
- with open('jsonfile.txt') as jsonfile:
- parsed = json. load(jsonfile)
- print json. dumps(parsed, indent=2, sort_keys=True)
The official Python documentation says __repr__() is used to compute the “official” string representation of an object. The repr() built-in function uses __repr__() to display the object. __repr__() returns a printable representation of the object, one of the ways possible to create this object.
67. Basically it contains all the attributes which describe the object in question. It can be used to alter or read the attributes. Quoting from the documentation for __dict__ A dictionary or other mapping object used to store an object's (writable) attributes.
__str__ is the output that is supposed to be human readable: __repr__ is supposed to be a representation readable for the Python interpreter (i.e. feeding the string to the interpreter should recreate the object). If an object does not have a __str__ method, however, __repr__ is used instead.
Similarly, using dir() to
see the contents of a module, or the attributes of an
object.
Take a look at the following built-in functions:
- type()
- dir()
- id()
- getattr()
- hasattr()
- globals()
- locals()
- callable()
Call str(object) on an object to convert it to a string.
- an_object = 5.
- object_string = str(an_object) Convert `an_object` to a string.
- print(object_string)
- print(type(object_string))
Accessing Attributes and Methods in Python
- getattr() – This function is used to access the attribute of object.
- hasattr() – This function is used to check if an attribute exist or not.
- setattr() – This function is used to set an attribute. If the attribute does not exist, then it would be created.
- delattr() – This function is used to delete an attribute.
To check if a variable contains a value that is a string, use the isinstance built-in function. The isinstance function takes two arguments. The first is your variable. The second is the type you want to check for.
Input string containing spaces
- int main() { char z[100];
- printf("Enter a string "); gets(z);
- printf("The string: %s ", z); return 0; }
The __str__ method is useful for a string representation of the object, either when someone codes in str(your_object) , or even when someone might do print(your_object) . The __str__ method is one that should be the most human-readable possible, yet also descriptive of that exact object.
The str() function converts values to a string form so they can be combined with other strings. For numbers, the standard operators, +, /, * work in the usual way. There is no ++ operator, but +=, -=, etc. work.
A string is a data type used in programming, such as an integer and floating point unit, but is used to represent text rather than numbers. It is comprised of a set of characters that can also contain spaces and numbers. For example, the word "hamburger" and the phrase "I ate 3 hamburgers" are both strings.
Methods are bound function objects. Methods are always bound to an instance of a user-defined class. Unbound methods (methods bound to a class object) are no longer available. PyTypeObject PyMethod_Type. This instance of PyTypeObject represents the Python method type.
Checking that method exists can be done by callable(getattr(object, method)) as already mentioned there. You can make use of dir() which is pre-defined in Python. If the object is an object of a pre-defined class such as int, str, etc. it displays the methods in it(You may know those methods as built in functions).
Python has a set of built-in
methods that you
can use on
lists/arrays.
Python List/Array Methods.
| Method | Description |
|---|
| clear() | Removes all the elements from the list |
| copy() | Returns a copy of the list |
| count() | Returns the number of elements with the specified value |
| extend() | Add the elements of a list (or any iterable), to the end of the current list |
out. println() calls toString() to
print the
output. If that
object's class does not override
Object.
Instead, these are the following ways we can print an array:
- Loops: for loop and for-each loop.
- Arrays. toString() method.
- Arrays. deepToString() method.
- Arrays. asList() method.
- Java Iterator interface.
- Java Stream API.
- public class Array { public static void main(String[] args) { int[] array = {1, 2, 3, 4, 5}; for (int element: array) { System.out.println(element); } } }
- import java.util.Arrays; public class Array { public static void main(String[] args) { int[] array = {1, 2, 3, 4, 5}; System.out.println(Arrays.toString(array)); } }
Object , the default toString method prints the name of the object's type (what class it is), followed by an @ sign, and the memory location of the object--the hexidecimal address of where that object is stored in memory. All objects inherit from java.
print(): print() method in Java is used to display a text on the console. This text is passed as the parameter to this method in the form of String. This method prints the text on the console and the cursor remains at the end of the text at the console.
The print(Object) method of PrintStream Class in Java is used to print the specified Object on the stream. This Object is taken as a parameter. Parameters: This method accepts a mandatory parameter object which is the Object to be printed in the Stream. Return Value: This method do not returns any value.
Let's see the simple code to convert String to Object in java.
- public class StringToObjectExample{
- public static void main(String args[]){
- String s="hello";
- Object obj=s;
- System.out.println(obj);
- }}
A toString() is an in-built method in Java that returns the value given to it in string format. Hence, any object that this method is applied on, will then be returned as a string object.
The toString() method returns the string representation of the object. If you print any object, java compiler internally invokes the toString() method on the object. So overriding the toString() method, returns the desired output, it can be the state of an object etc. depends on your implementation.
Creating an Object
- Declaration − A variable declaration with a variable name with an object type.
- Instantiation − The 'new' keyword is used to create the object.
- Initialization − The 'new' keyword is followed by a call to a constructor. This call initializes the new object.
