通过 function 迭代列表继续返回 Nonetype

Question

So I was trying to iterate this list techno_list1 = ["C", "C#", "C++", "Java", "JavaScript", "Python", "Scala", "Oracle", "SQL Server", "MySQL Server", "PostgreSQL", "MongoDB"] through a function that return the number of job related to the keyword inside the list below is the function:

 def get_number_of_jobs(technology): number_of_jobs = 0 page=0 new_results=1 while new_results>0: paras={"description":technology,"page":page} r=requests.get(baseurl,paras) new_results=len(r.json()) page+=1 number_of_jobs+=(len(r.json())) return technology,number_of_jobs

It return a tuple like this ('C', 239) ('C#', 50) ('C++', 32) ('Java', 138) ('JavaScript', 116) ('Python', 98) ('Scala', 94) ('Oracle', 18) ('SQL Server', 28) ('MySQL Server', 14) ('PostgreSQL', 22) ('MongoDB', 14) So I thought it should be a tuple but when checking using type() it keep returning <class 'NoneType'>

I want it to be either List or Tuple is there anyway to change the data type?

Answer 1

Ok here is what I encountered:

 techno_list1 = ["C", "C#", "C++", "Java", "JavaScript", "Python", "Scala", "Oracle", "SQL Server", "MySQL Server", "PostgreSQL", "MongoDB"] def number_of_each(techno_list): for x in techno_list: print(get_number_of_jobs(x)) print(type(number_of_each(techno_list1)))

Then the result:

 ('C', 239) ('C#', 50) ('C++', 32) ('Java', 138) ('JavaScript', 116) ('Python', 98) ('Scala', 94) ('Oracle', 18) ('SQL Server', 28) ('MySQL Server', 14) ('PostgreSQL', 22) ('MongoDB', 14) <class 'NoneType'>

Maybe it a bug?

Answer 2

From you extended elaboration, I can see that you are printing the type of number_of_each(techno_list1) .

However, this function is currently not returning anything, it simply just prints out the values you obtained through get_number_of_jobs() . This is why it is returning <class 'NoneType'> .

I would create a list outside of the function number_of_each() and then add the items to the list to print out later, try this:

 techno_list1 = ["C", "C#", "C++", "Java", "JavaScript", "Python", "Scala", "Oracle", "SQL Server", "MySQL Server", "PostgreSQL", "MongoDB"] job_numb = [] def number_of_each(techno_list): for x in techno_list: job_numb.append(get_number_of_jobs(x)) print(type(get_number_of_jobs(x)) print(job_numb)

The type being printed now should be <class 'list'> for job_numb and <class 'tuple'> for the return of get_number_of_jobs() or any items in job_numb .

Realistically, this does not really change anything. You already have a tuple returned by the get_number_of_jobs() function. You are just misprinting the right variable.