Python Class - Can't find out how to use method return value within another method-CodePudding

So this is the class i'm testing:

class Test:

    def find_string(self, string):
        self.string = string
        return string.find(string)

    def add_string(self, string):
        found = self.find_string('bar')

        if found == -1:
            string = string   ' bar'
            
        return string

Here is my setup:

test_string = 'foo'

Test1 = Test()
new_string = Test1.add_string(string)

Results

Expected result: foo bar
Result: foo

If I replace the method call in add_string with the direct function find() it works fine. Please help me.

CodePudding user response：

As for me all problem is that variables have similar names and this can be misleading.

Your string.find(string) means "bar".find("bar") but you expect "foo".find("bar")

You would have to use self.string = string in add_string() (instead of find_string()) and later in find_string() use self.string.find(string) instead of string.find(string) - and then you will have "foo" in self.string and "bar" in string so finally self.string.find(string) will mean "foo".find("bar")

class Test:

    def find_string(self, string):
        return self.string.find(string)

    def add_string(self, string):
        self.string = string

        found = self.find_string('bar')

        if found == -1:
            string = string   ' bar'
            
        return string

# --- main ---

test_string = 'foo'

test = Test()   # PEP8: `lower_case_names` for variables 
new_string = test.add_string(test_string)

print(new_string)

PEP 8 -- Style Guide for Python Code