how do i change a variable in a class(python)

Question

my code goes like this

global php
php = 1
class add_s_f_g_v_php:
  def r(php):
    phpt = php
    php = phpt+phpt
    return php
  
    

add_s_f_g_v_php.r(php)
print(php)

and it gives me 1 like it didn't change

I tryed adding return and making the var global.

Answer 1

You should put global inside function:

php = 1
class add_s_f_g_v_php:
  def r(php):
    global php
    phpt = php
    php = phpt+phpt
  
    

add_s_f_g_v_php.r(php)
print(php)

OR Re-assign back

php = 1
class add_s_f_g_v_php:
  def r(php):
    phpt = php
    php = phpt+phpt
    return php
  
    

php = add_s_f_g_v_php.r(php)
print(php)

Answer 2

I usually avoid this kind of problem. Most of the time if you need to do this, there is probably a design flaw somewhere. Anyhow, I see two ways of doing it without reassignment. Both use, as in the other answers, the global keyword (Note: I do not see how---in the present form---the other answers actually would work).

php = 1
print( php )

class changer( object ): ## object not required in Python3 but I am used to put it

    #method 1
    def php_adder_1( self, adder ):
        global php
        php += adder

    #method 2
    @classmethod
    def php_adder_2( cls, adder ):
        global php
        php += adder

### is applied in the following ways:
myobj = changer()
myobj.php_adder_1( 3 )
print( php )

changer().php_adder_2( 30 )
print( php )

### and this would also work
myobj.php_adder_2( 300 )
print( php )

providing

>> 1
>> 4
>> 34
>> 334

Check out, eg, this on @classmethod