def section_articles():

    Biology = (df2["Section"]=="Biology").sum()
    Chemistry = (df2["Section"]=="Chemistry").sum()
    Computer_Science = (df2["Section"]=="Computer Science").sum()
    Earth_Environment = (df2["Section"]=="Earth & Environment").sum()
    Mathematics = (df2["Section"]=="Mathematics").sum()
    Physics = (df2["Section"]=="Physics").sum()
    Statistics = (df2["Section"]=="Statistics").sum()

    return() 
print ("Biology",Biology)
print ("Chemistry",Chemistry)
print ("Computer_Science",Computer_Science)
print ("Earth_Environment",Earth_Environment)
print ("Mathematics",Mathematics)
print ("Physics",Physics)
print ("Statistics",Statistics)

section_articles()

I am expecting the number of articles in each section butgetting : Biology is not defined as error can someone help me please

CodePudding user response：

The issue is that the variables Biology, Chemistry, etc. are local variables defined inside the section_articles function, so they are not accessible outside of the function. To access the values returned by the function, you need to assign the function's output to a variable:

def section_articles():
    Biology = (df2["Section"]=="Biology").sum()
    Chemistry = (df2["Section"]=="Chemistry").sum()
    Computer_Science = (df2["Section"]=="Computer Science").sum()
    Earth_Environment = (df2["Section"]=="Earth & Environment").sum()
    Mathematics = (df2["Section"]=="Mathematics").sum()
    Physics = (df2["Section"]=="Physics").sum()
    Statistics = (df2["Section"]=="Statistics").sum()

    return (Biology, Chemistry, Computer_Science, Earth_Environment, Mathematics, Physics, Statistics)

section_counts = section_articles()

print ("Biology",section_counts[0])
print ("Chemistry",section_counts[1])
print ("Computer_Science",section_counts[2])
print ("Earth_Environment",section_counts[3])
print ("Mathematics",section_counts[4])
print ("Physics",section_counts[5])
print ("Statistics",section_counts[6])

An optimized version by using a dictionary to store the values of each section and then looping through the dictionary to print the values:

def section_articles():
    sections = {"Biology": (df2["Section"]=="Biology").sum(),
                "Chemistry": (df2["Section"]=="Chemistry").sum(),
                "Computer Science": (df2["Section"]=="Computer Science").sum(),
                "Earth & Environment": (df2["Section"]=="Earth & Environment").sum(),
                "Mathematics": (df2["Section"]=="Mathematics").sum(),
                "Physics": (df2["Section"]=="Physics").sum(),
                "Statistics": (df2["Section"]=="Statistics").sum()}
    return sections

section_counts = section_articles()

for section, count in section_counts.items():
    print(f"{section}: {count}")

CodePudding user response：

Your function returns an empty tuple () so you can't ask for its variables outside it.

One way to to fix the error and reduce visible noise is to make/return a dictionnary and loop:

def section_articles():
    list_of_sections = ["Biology", "Chemistry", "Computer Science",
                        "Earth & Environment", "Mathematics", "Physics", "Statistics"]
    return {k: (df2["Section"] == k).sum() for k in sections}

for k, v in section_articles().items():
    print(k, v)

Another variant :

list_of_sections = ["Biology", "Chemistry", "Computer Science",
                    "Earth & Environment", "Mathematics", "Physics", "Statistics"]

def section_articles(section):
    return (df2[section] == k).sum()


for section in list_of_sections:
    print(section, section_articles(section))