Confusion in Python Pandas code

Question

Can you explain this code to me?

import pandas as pd

data = pd.read_csv("SalaryGender.csv")
df = pd.DataFrame(data, columns=["Salary", "Gender", "Age", "PhD"])
print(df)
selected_data = df.loc[:, ["Age", "PhD"]]
print(selected_data)
i=PhD
for i in selected_data.iter_items():
if i == 0:
del i
I understood the dataframe creation but I am not able to understand the logic. 

Answer 1

I have added the explanation of code as comments for each line. Please refer it.

import numpy, pandas   # import libraries 

df = pandas.read_csv('SalaryGender.csv', delimiter=',') # reading salarygender data.

salary = numpy.array(df['Salary']) # getting Salary column from pandas data frame and converting into numpy array

gender = numpy.array(df['Gender'] ) # getting Gender column from pandas data frame and converting into numpy array

phd = numpy.array(df['PhD'])  # getting PhD column from pandas data frame and converting into numpy array

age = numpy.array(df['Age'])  # getting Age column from pandas data frame and converting into numpy array


frame = pandas.DataFrame() #creating new data frame with Age and PhD column

frame["Age"] = age

frame["PhD"] = phd

# dropping rows where PhD is 0 using for loop

for i in range(0, 100):

    if frame.loc[i]["PhD"] == 0:

        frame = frame.drop(i)


print(frame) # Printing data frame after dropping rows where PhD is 0