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How to not duplicate elements when entering array in csv

I have a piece of code used to enter student information. But I want to transform it so that Admission no. cannot be repeated, when entering an existing number, a message will be printed if you want to re-enter an existing number. below is my code
import csv
student_fields = ['Admission no.','Name','Age','Email','Phone']
student_database = 'students.csv'
def add_student():
print("-------------------------")
print("Add Student Information")
print("-------------------------")
global student_fields
global student_database
student_data = []
for field in student_fields:
print(field)
value = input("Enter " + field + ": ")
student_data.append(value)
with open(student_database,"a",encoding = "utf-8") as f:
writer = csv.writer(f)
writer.writerows([student_data])
print("Data saved successfully")
input("Press any key to continue")
return

You can do something like this. As Barmar suggested, put the admission numbers in a set at the start of your definition. Then, check the user's input against those numbers. Create a while loop that doesn't let the user input any other value until they enter a new Admission no (and tell them that they are entering a duplicate admission number). Once everything looks good, write it to the csv.
import csv
student_fields = ['Admission no.','Name','Age','Email','Phone']
student_database = 'students.csv'
def add_student():
print("-------------------------")
print("Add Student Information")
print("-------------------------")
global student_fields
global student_database
# create a set of the already entered admission numbers
with open('students.csv', 'r') as file:
reader = csv.reader(file)
admissionNums = {x[0] for x in reader if x}
student_data = []
for field in student_fields:
print(field)
value = input("Enter " + field + ": ")
# while the user is entering the admission no. field and they are entering a duplicate, keep prompting them for a new/unique number
while field == 'Admission no.' and value in admissionNums:
print("Admission no. already in file, try again")
value = input("Enter " + field + ": ")
student_data.append(value)
# I also added `newline=''` so that it would stop creating an empty row when writing to the file
# You can remove this if you want to keep making a new row every time you write to it
with open(student_database,"a",encoding = "utf-8", newline='') as f:
writer = csv.writer(f)
writer.writerows([student_data])
print("Data saved successfully")
input("Press any key to continue")
# The return statement here is not necessary

Michael Dawson's trivia game assignment

Please help me to understand what I'm doing wrong.
I'm getting error
NameError: name 'name' is not defined
Regardless function welcome returns name.
Here's the code.
import sys, pickle, shelve
def open_file(file_name, mode):
"""Open a file."""
try:
the_file = open(file_name, mode)
except IOError as e:
print("Unable to open the file", file_name, "Ending program.\n", e)
input("\n\nPress the enter key to exit.")
sys.exit()
else:
return the_file
def next_line(the_file):
"""Return next line from the trivia file, formatted."""
line = the_file.readline()
line = line.replace("/", "\n")
return line
def next_block(the_file):
"""Return the next block of data from the trivia file."""
category = next_line(the_file)
question = next_line(the_file)
answers = []
for i in range(4):
answers.append(next_line(the_file))
correct = next_line(the_file)
if correct:
correct = correct[0]
score = next_line(the_file)
explanation = next_line(the_file)
return category, question, answers, correct, score, explanation
def welcome(title):
"""Welcome the player and get his/her name."""
print("\t\tWelcome to Trivia Challenge!\n")
print("\t\t", title, "\n")
name = input('Enter your name')
return name
def pic_save(name, final_score):
records = {name: final_score}
f = open('pickles.dat', 'ab')
pickle.dump(records, f)
return records
def pic_read():
f = open("pickles.dat", "rb")
records = pickle.load(f)
print(records)
f.close()
def main():
trivia_file = open_file("7.1.txt", "r")
title = next_line(trivia_file)
welcome(title)
final_score = 0
# get first block
category, question, answers, correct, score, explanation = next_block(trivia_file)
while category:
# ask a question
print(category)
print(question)
for i in range(4):
print("\t", i + 1, "-", answers[i])
# get answer
answer = input("What's your answer?: ")
# check answer
if answer == correct:
print("\nRight!", end=" ")
final_score += int(score)
print("Score:", score, "\n\n")
else:
print("\nWrong.", end=" ")
print(explanation)
# get next block
category, question, answers, correct, score, explanation = next_block(trivia_file)
trivia_file.close()
pic_save(name, final_score)
print("That was the last question!")
print("You're final score is", final_score)
pic_read()
main()
input("\n\nPress the enter key to exit.")

Probably what you want to do is assign the return value of welcome to a variable named name, otherwise the return value is lost.
name = welcome(title)

Python for absolute beginners chapter 7 challenge 2

I am currently working through the python for absolute beginners 3rd addition. I am struggling with the 2nd challenge in the 7th chapter of the book, as i keep getting an error i don't understand.
The challenge is to:
"improve triva challenge game so that it maintains a high score list in a file. The program should records the player's name and score if the player makes the list. store the high scores using a pickled object."
The original code
# Trivia Challenge
# Trivia game that reads a plain text file
import sys
def open_file(file_name, mode):
"""Open a file."""
try:
the_file = open(file_name, mode)
except IOError as e:
print("Unable to open the file", file_name, "Ending program.\n", e)
input("\n\nPress the enter key to exit.")
sys.exit()
else:
return the_file
def next_line(the_file):
"""Return next line from the trivia file, formatted."""
line = the_file.readline()
line = line.replace("/", "\n")
return line
def next_block(the_file):
"""Return the next block of data from the trivia file."""
category = next_line(the_file)
question = next_line(the_file)
answers = []
for i in range(4):
answers.append(next_line(the_file))
correct = next_line(the_file)
if correct:
correct = correct[0]
explanation = next_line(the_file)
return category, question, answers, correct, explanation
def welcome(title):
"""Welcome the player and get his/her name."""
print("\t\tWelcome to Trivia Challenge!\n")
print("\t\t", title, "\n")
def main():
trivia_file = open_file("trivia.txt", "r")
title = next_line(trivia_file)
welcome(title)
score = 0
# get first block
category, question, answers, correct, explanation = next_block(trivia_file)
while category:
# ask a question
print(category)
print(question)
for i in range(4):
print("\t", i + 1, "-", answers[i])
# get answer
answer = input("What's your answer?: ")
# check answer
if answer == correct:
print("\nRight!", end=" ")
score += 1
else:
print("\nWrong.", end=" ")
print(explanation)
print("Score:", score, "\n\n")
# get next block
category, question, answers, correct, explanation = next_block(trivia_file)
trivia_file.close()
print("That was the last question!")
print("You're final score is", score)
main()
input("\n\nPress the enter key to exit.")
my attempt at the challenge code
# Trivia Challenge
# Trivia game that reads a plain text file
import sys, pickle
def open_file(file_name, mode):
"""Open a file."""
try:
the_file = open(file_name, mode)
except IOError as e:
print("Unable to open the file", file_name, "Ending program.\n", e)
input("\n\nPress the enter key to exit.")
sys.exit()
else:
return the_file
def next_line(the_file):
"""Return next line from the trivia file, formatted."""
line = the_file.readline()
line = line.replace("/", "\n")
return line
def next_block(the_file):
"""Return the next block of data from the trivia file."""
category = next_line(the_file)
points = next_line(the_file)
question = next_line(the_file)
answers = []
for i in range(4):
answers.append(next_line(the_file))
correct = next_line(the_file)
if correct:
correct = correct[0]
explanation = next_line(the_file)
return category, points, question, answers, correct, explanation
def welcome(title):
"""Welcome the player and get his/her name."""
print("\t\tWelcome to Trivia Challenge!\n")
print("\t\t", title, "\n")
def high_scores():
global score
value = int(score)
name = input("What is your name? ")
entry = (value, name)
f = open("high_scores.dat", "wb+")
high_scores = pickle.load(f)
high_scores.append(entry)
high_scores = high_scores[:5]
print("High Scores\n")
print("NAME\tSCORE")
for entry in high_scores:
value, name = entry
print(name, "\t", value)
pickle.dump(high_scores, f)
f.close()
def main():
trivia_file = open_file("trivia.txt", "r")
title = next_line(trivia_file)
welcome(title)
# get first block
category, points, question, answers, correct, explanation = next_block(trivia_file)
while category:
# ask a question
print(category)
print(question)
for i in range(4):
print("\t", i + 1, "-", answers[i])
# get answer
answer = input("What's your answer?: ")
# check answer
if answer == correct:
print("\nRight!", end=" ")
j = int(points)
global score
score += j
else:
print("\nWrong.", end=" ")
print(explanation)
print("Score:", score, "\n\n")
# get next block
category, points, question, answers, correct, explanation = next_block(trivia_file)
trivia_file.close()
print("That was the last question!")
print("You're final score is", score)
high_scores()
score = 0
main()
input("\n\nPress the enter key to exit.")
And the wonderfully confusing error
Traceback (most recent call last):
File "C:\Users\Cheyne\Desktop\Python\chapter07\Challenges\temp.py", line 104, in <module>
main()
File "C:\Users\Cheyne\Desktop\Python\chapter07\Challenges\temp.py", line 100, in main
high_scores()
File "C:\Users\Cheyne\Desktop\Python\chapter07\Challenges\temp.py", line 54, in high_scores
high_scores = pickle.load(f)
File "C:\Python31\lib\pickle.py", line 1365, in load
encoding=encoding, errors=errors).load()
EOFError
Can anyone help explain what's going wrong here please? I have been staring at it for days.

You have an "EOFError", which is an "End Of File Error" at line 54.
That's where you try to load the pickle file so, considering that you are not checking that the file actually exists, my guess is that you have no file and get the error.
Either create an initial file by yourself, or check that it exists and is valid before trying to load it.
EDIT: I just noticed that you open the pickle file as "wb+", which means that you open it for writing and try to read it. You're overwriting the file, which becomes zero bytes. If you want to append to the existing file, you should use "a" instead of "w". Again, before loading make sure the file contains valid data.

Golf scores python program

I am trying to create two programs one that writes the data to file golf.txt and the second which reads the records from golf.txt and displays them. The first program I am trying to get the program to quit when you leave the input field blank. Here's my code for the first program.
#Program that reads each player's name and golf score as input
#Save to golf.txt
outfile = open('golf.txt', 'w')
#Enter input, leave blank to quit program
while True:
name = input("Player's name(leave blank to quit):")
score = input("Player's score(leave blank to quit):")
if input ==" ":
break
#write to file golf.txt
outfile.write(name + "\n")
outfile.write(str(score) + "\n")
outfile.close()
With the second program I can't get the program to display the output I want on one line. Here's the second program.
#Golf Scores
# main module/function
def main():
# opens the "golf.txt" file created in the Golf Player Input python
# in read-only mode
infile = open('golf.txt', 'r')
# reads the player array from the file
player = infile.read()
# reads the score array from the file
score = infile.read()
# prints the names and scores
print(player + "scored a" + score)
# closes the file
infile.close()
# calls main function
main()
Any help or suggestions I can get would be greatly appreciated.

Two main problems:
1.) you first code has if input == ' ' which is wrong in two ways:
input is a function. you already saved the input so you should be comparing with name and score.
input returns a '' when you dont input anything, not a ' '.
so change to: if name == '' or score == '': or even if '' in (name,score): (does the same things)
2.) file.read() will automatically read EVERYTHING in the file as one string. You want to split it into each component so you can either do something like:
player,score = file.readlines()[:2]
or
player = file.readline()
score = file.readline()
then print (with leading and trailing spaces in your middle string!)
print(player + " scored a " + score)

Got both programs working
program 1:
#Program that reads each player's name and golf score as input
#Save to golf.txt
outfile = open('golf.txt', 'w')
#Enter input, leave blank to quit program
while True:
name = input("Player's name(leave blank to quit):")
if name == "":
break
score = input("Player's score:")
#write to file golf.txt
outfile.write(name + "\n")
outfile.write(str(score) + "\n")
outfile.close()
program 2:
#Golf Scores
# main module/function
def main():
# opens the "golf.txt" file created in the Golf Player Input python
# in read-only mode
infile = open('golf.txt', 'r')
# reads the player array from the file
name = infile.readline()
while name != '':
# reads the score array from the file
score = infile.readline()
# strip newline from field
name = name.rstrip('\n')
score = score.rstrip('\n')
# prints the names and scores
print(name + " scored a " + score)
# read the name field of next record
name = infile.readline()
# closes the file
infile.close()
# calls main function
main()

Eliminate spaces from the input before checking (I would use .strip() method). And compare it to the empty string "" instead of space(s) " ".

With the "while true" block you keep asking and taking the names and the scores, but you overwrite them so you always will have just the last pair.
You need to keep them all, so you can make a list:
names_and_scores = []
while True:
name = input("Player's name(leave blank to quit):").strip()
if name == "":
break
score = input("Player's score:").strip()
if name != "" and score != "":
names_and_scores.append("{}; {}".format(name, score))
with open('golf.txt', 'w') as outfile:
outfile.write("\n".join(names_and_scores))
The second program opens the file, read lines one by one, splits them and print:
with open('golf.txt', 'r') as infile:
for line in infile:
name, score = line.strip().split("; ")
print("{} scored a {}.".format(name, score))

Pickle in Python

How do you save and load a variable using pickle? I am trying to save and load a high score from a trivia game. Here is the relevant code:
high_scorz=open_file("high.dat", "wb+")
high = 0
try:
high=pickle.load(high_scorz)
except EOFError:
print("EOF ERROR!!!!")
finally:
print("NO DATA RECEIVED")
# later in the code when score has been updated
if score > high:
pickle.dump(score, high_scorz)
high = score
trivia_file.close()
high_scorz.close()
print("High Scorz: " + str(high))
The problem is every time score and high are equal. high = 0 every time because every time I receive a end of file error. Therefor when I run the final print statement it always prints the current score.
Heres all of the code if you want it:
# Trivia Challenge
# Trivia game that reads a plain text file
import pickle
import sys
def open_file(file_name, mode):
"""Open a file."""
try:
the_file = open(file_name, mode)
except IOError as e:
print("Unable to open the file", file_name, "Ending program.\n", e)
input("\n\nPress the enter key to exit.")
sys.exit()
else:
return the_file
def next_line(the_file):
"""Return next line from the trivia file, formatted."""
line = the_file.readline()
line = line.replace("/", "\n")
return line
def next_block(the_file):
"""Return the next block of data from the trivia file."""
category = next_line(the_file)
question = next_line(the_file)
answers = []
for i in range(4):
answers.append(next_line(the_file))
correct = next_line(the_file)
if correct:
correct = correct[0]
points = next_line(the_file)
explanation = next_line(the_file)
return category, question, answers, correct, points, explanation
def welcome(title):
"""Welcome the player and get his/her name."""
print("\t\tWelcome to Trivia Challenge!\n")
print("\t\t", title, "\n")
def main():
trivia_file = open_file("trivia.txt", "r")
high_scorz=open_file("high.dat", "wb+")
high = 0
try:
high=pickle.load(high_scorz)
except EOFError:
print("EOF ERROR!!!!")
finally:
print("NO DATA RECEIVED")
title = next_line(trivia_file)
welcome(title)
score = 0
# get first block
category, question, answers, correct, points, explanation = next_block(trivia_file)
while category:
# ask a question
print(category)
print(question)
for i in range(4):
print("\t", i + 1, "-", answers[i])
# get answer
answer = input("What's your answer?: ")
# check answer
if answer == correct:
print("\nRight!", end=" ")
score += int(points)
else:
print("\nWrong.", end=" ")
print(explanation)
print("Score:", score, "\n\n")
# get next block
category, question, answers, correct, points, explanation = next_block(trivia_file)
print("That was the last question!")
print("You're final score is", score)
if score > high:
pickle.dump(score, high_scorz)
high = score
trivia_file.close()
high_scorz.close()
print("High Scorz: " + str(high))
main()
input("\n\nPress the enter key to exit.")

If you open with a w mode, you overwrite any previous data. It would be easier to open the file twice:
filename = "high.dat"
with open(filename) as high_scores:
try:
high_score = pickle.load(high_scores)
except Exception:
print("No data loaded")
high_score = 0
# later in the code when score has been updated
if score > high_score:
with open(filename, 'w') as high_scores:
pickle.dump(score, high_scores)
high_score = score