Develop Reference

Can't run through a list in print function

I'm a beginner to python. I've written this code but I can't execute the for loop inside the print function to iterate through the list of marks:
class student:
def __init__(self, name, age, iden, lMark):
self.name=name
self.age=age
self.iden=iden
self.lMark=lMark
def printAve(self, obj):
for i in obj.lMark:
res+=i
av=res/len(lMark)
return av
def disInfo(self, obj):
print("the name is: ",obj.name)
print("the age is: ",obj.age)
print("the identity is: ",obj.iden)
print("the marks are: ", for i in lMark:
print(i))
def addStudent(self, n, a, i, l):
ob=student(n,a,i,l)
ls.append(ob)
return true
def searchStudent(self, _val):
for i in len(ls):
if ls[i]==_val:
return i
ls=[]
s=student("Paul", 23,14, list(15,16,17,20,12))
bool added = s.add("Van", 20, 12, list(12,18,14,16))
if added==True:
print("Student added successfully")
for i in range(ls.__len__())
s.disInfo(ls[i])
Can someone help me to solve this problem and explain me how to do?

You can't put a bare for loop in the argument list to print, and of course the embedded print doesn't return what it prints. What you can do is
print("the marks are:", ", ".join(lMark))
or perhaps
print("the marks are:", *lMark)
(Also, I believe you mean obj.lMark.)
To reiterate, if you call some code in the argument to print, that code should evaluate to the text you want print to produce; not do printing on its own. For example,
def pi()
return 3.141592653589793 # not print(3.141592653589793)
def adjective(arg):
if arg > 100:
return "big" # not print("big")
else:
return "small" # not print("small")
print(str(pi()), "is", adjective(pi()))
Notice how each function call returns something, and the caller does something with the returned value.

from statistics import mean
# classes are named LikeThis
# constants named LIKE_THIS
# other variables should be named like_this
# hungarian notation is not used in Python
class Student:
# instead of a global variable named ls,
# I'm using a class variable with a clear name instead
all_students = []
def __init__(self, name, age, iden, marks):
self.name = name
self.age = age
self.iden = iden
self.marks = marks
def printAve(self):
# you don't need to pass two arguments when you're only operating on a single object
# you don't need to reinvent the wheel, see the import statement above
return mean(self.marks)
def disInfo(self):
print("the name is:", self.name)
print("the age is:", self.age)
print("the identity is:", self.iden)
# you can't put a statement inside of an expression
# I'm guessing you want the marks all on the same line?
# the *args notation can pass any iterable as multiple arguments
print("the marks are:", *self.marks)
# this makes more sense as a classmethod
# clear variable names are important!
#classmethod
def addStudent(cls, name, age, iden, marks):
# I'm using cls instead of Student here, so you can subclass Student if you so desire
# (for example HonorStudent), and then HonorStudent.addStudent would create an HonerStudent
# instead of a plain Student object
cls.all_students.append(cls(name, age, iden, marks))
# note the capital letter!
return True
# again, this should be a classmethod
#classmethod
def searchStudent(cls, student):
# use standard methods!
try:
return cls.all_students.index(student)
except ValueError:
return None
# the literal syntax for lists in Python is `[1, 2, 3]`, _not_ `list(1, 2, 3)`.
# it also makes more sense to use Student.addStudent here, because just calling Student() doesn't add it
# to the list (although you could do that in __init__ if you always want to add them to the list)
Student.addStudent("Paul", 23, 14, [15, 16, 17, 20, 12])
# in Python, type annotations are optional, and don't look like they do in C or Java
# you also used `add` instead of `addStudent` here!
added: bool = Student.addStudent("Van", 20, 12, [12,18,14,16])
# don't need == True, that's redundant for a boolean value
if added:
print("Student added successfully")
# never call `x.__len__()` instead of `len(x)`
# (almost) never use `for i in range(len(x))` instead of `for item in x`
for student in Student.all_students:
student.disInfo()

First I answer your initial question, you can print a list in different ways, here are some of them.
You can iterate through it with a for loop and print every element on a different line:
for elem in self.lMark:
print(elem)
You can also append all values to a string and separate them by a character or something.
(Note: There will be a trailing space at the end.)
myString = ""
for elem in self.lMark:
myString = myString + str(elem) + " "
print(myString)
Better is this by doing it with strings-join method and a short version of the container iteration:
", ".join([str(i) for i in self.lMark])
There were some more issues in the code example.
Here is a running version of the script:
class Student:
def __init__(self, name, age, iden, lMark):
self.name=name
self.age=age
self.iden=iden
self.lMark=lMark
def printAve(self, obj):
for i in obj.lMark:
res+=i
av=res/len(self.lMark)
return av
def disInfo(self):
print("the name is: ",self.name)
print("the age is: ",self.age)
print("the identity is: ",self.iden)
print("the marks are: ", ", ".join([str(i) for i in self.lMark]))
class StudentList:
def __init__(self):
self.__list_of_students = []
def add(self, s):
self.__list_of_students.append(s)
return True
def get(self):
return self.__list_of_students
def search(self, name):
for s in self.__list_of_students:
if s.name == name:
return s
return None
ls = StudentList()
s=Student("Paul", 23,14, [15,16,17,20,12])
ls.add(s)
added = ls.add(Student("Van", 20, 12, [12,18,14,16]))
if added:
print("Student added successfully")
search_name1 = "Paula"
search_name2 = "Van"
if ls.search(search_name1):
print(search_name1, "is part of the list!")
else:
print("There is no", search_name1)
if ls.search(search_name2):
print(search_name2, "is part of the list!")
else:
print("There is no", search_name2)
for student in ls.get():
student.disInfo()
print("-"*10)
I would suggest to separate the list of students and the students to two different classes as shown in the code above.

You can unpack your list with the * operator:
print("the marks are: ", *lMark)

Try setting this as a function. i.e
def quantity():
for i in lMark:
print(i)
Then,
def disInfo(self, obj):
print("the name is: ",obj.name)
print("the age is: ",obj.age)
print("the identity is: ",obj.iden)
print("the marks are: ", + quantity)

Call to a variable that is inside another function

def HOME():
""" The first screen
"""
print ('Welcome to my program!')
input_grocery_list = input('Hello, please enter here a list of groceries: ')
def input_to_list():
""" This f takes the input
and put it inside a list
without the: ','
and print the list
"""
new_grocery_list = []
separator = ", "
while ',' in input_grocery_list:
d = input_grocery_list.index(',')
y = input_grocery_list[:d]
new_grocery_list.append(y)
input_grocery_list = input_grocery_list[(d+1):]
if ',' not in input_grocery_list:
new_grocery_list.append(input_grocery_list)
print(separator.join(new_grocery_list))
def the_groceries_list():
""" Do somthing to the first input
accord to the next choice
"""
print("You can chose a number betwen 1 - 9 n/ and we do the rest..")
grocery_list = input('please enter here your choice : ')
if grocery_list == '1':
input_to_list(input_grocery_list)
if len(input_grocery_list) != 0:
the_groceries_list()
HOME()
The error
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 37, in HOME
File "<stdin>", line 34, in the_groceries_list
TypeError: input_to_list() takes 0 positional arguments but 1 was given
My problem is probably in the second function called "input_to_list ()"
  While I am trying to read / change the "input_grocery_list" variable that is inside the first function (HOME)
It does not recognize him.
I tried to fix it using global or self but I probably don't really know where exactly to put them because in the meantime it didn't work for me.
Anyone know how I can fix this?

As I can see, you try to have a main function, but you should use a class instead of a function, so more like this.
class Home():
def __init__(self):
"""
define your class wide variables here as following
"""
# example
# self.your_name = 'hello'
# to access it in an function IN this class, type: self.your_name
pass
def get_items(self):
print('Welcome to my program!')
input_grocery_list = input('Hello, please enter here a list of groceries (sep with comma): ')
self.input_to_list(input_grocery_list)
# you forgot this
# ||
# \/
def input_to_list(self, grocery_list: str):
""" This f takes the input
and put it inside a list
without the: ','
and print the list
"""
new_grocery_list = grocery_list.split(',')
# to print as list
print(new_grocery_list)
# to print every item in list
for item in new_grocery_list:
print(item)
# print('List End') # if you want to
# I don't really know what that is supposed to do, but whatever it is it wont
"""
def the_groceries_list(self):
# Do somthing to the first input
# accord to the next choice
print("You can chose a number betwen 1 - 9 n/ and we do the rest..")
grocery_list = input('please enter here your choice : ')
if grocery_list == '1':
input_to_list(input_grocery_list)
if len(input_grocery_list) != 0:
the_groceries_list()
"""
# to use this class and it's functions first create an object
home = Home()
# than call a function
home.get_items()
I wont go into details of Classes and Object but here is a link for you.
Read this, it should explain the basics pretty good.

You need to change definition of your nested function so it can take args:
def input_to_list(input_grocery_list):

NameError in Python - not sure if the class or the function is causing the error

I have a text file describing resumes where each line looks like:
name university sex filename
So one line would say something like
John Texas M resume1.doc
The file has standard formatting and does not contain any errors. There are four possible names and four possible universities, randomized to create 64 resumes. I'm trying to write a program that reads through the text file, creates a resume object with attributes for the name, university, sex, and filename, and adds these objects to a list of resume objects. I have a lot of experience in C++, but this is my first Python program and I'm getting thrown off by an error:
File "mycode.py", line 142, in <module>
resumes()
File "mycode.py", line 65, in resumes
r = resume(name,uni,sex,filename)
NameError: global name "name" is not defined
My code looks like:
class resume:
def __init__(self, name, uni, sex, filename)
self.name = name
self.uni = uni
self.sex = sex
self.filename = filename
mylist[]
def resumes():
f = open("resumes.txt",'r')
for line in f:
for word in line.split():
if word == ("John" or "Fred" or "Jim" or "Michael"):
name = word
elif word == ("Texas" or "Georgia" or "Florida" or "Montana"):
uni = word
elif word == "M":
sex = word
elif re.match(r'\w\.doc',word):
filename = word
r = resume(name,uni,sex,filename)
mylist.insert(r)
I'm not sure if the error is in the class or the function. My computer isn't showing any syntax errors but I'm new to this so if there are, please feel free to tell me how to fix them.
I've tried defining name, uni, etc. outside the "for word in line.split()" loop but the program still had an issue with the line "r = resume(name,uni,sex,filename)" so I'm not sure what the issue is. I've read through other answers about NameError but I'm new to Python and couldn't figure out the equivalent problem in my code.

The NameError is caused by undefined variables in cases where no values are found in the text file. Define them within the function before you try to assign values from the text file to them:
def resumes():
f = open("resumes.txt",'r')
for line in f:
name = ""
uni = ""
sex = ""
filename = ""
for word in line.split():
...
You can also pre-define the variables in your class initialization by using keyword arguments if you like (this isn't the cause of the NameError though):
class resume:
def __init__(self, name="", uni="", sex="", filename="")
self.name = name
self.uni = uni
self.sex = sex
self.filename = filename
Defining a list in python is done by typing mylist = [], not mylist[]. Also, at the moment, the list would be defined in the global namespace which is generally discouraged. Instead, you can make resumes return a list and assign this value to mylist:
def resumes():
resume_list = []
f = open("resumes.txt",'r')
for line in f:
for word in line.split():
if word == ("John" or "Fred" or "Jim" or "Michael"):
name = word
elif word == ("Texas" or "Georgia" or "Florida" or "Montana"):
uni = word
elif word == "M":
sex = word
elif re.match(r'\w\.doc',word):
filename = word
r = resume(name,uni,sex,filename)
resume_list.insert(r)
return resume_list
Then you can do the following anywhere in your code:
mylist = resumes()
Remember to close files after opening them; in your case by calling f.close() after processing all the lines. Even better, have python manage it automatically by using the context manager with so you don't have to call f.close():
def resumes():
with open("resumes.txt",'r') as f:
for line in f:
...
Typically, you'd use append rather than insert when working with lists. insert takes two arguments (position/index, and the element to insert) so mylist.insert(r) should raise a TypeError: insert() takes exactly 2 arguments (1 given). Instead, do mylist.append(r) to insert r after the last element in the list.
As, johnrsharpe pointed out in the comments, your word comparisons probably aren't doing what you expect. See this example:
>>> word = "John"
>>> word == ("John" or "Fred" or "Jim" or "Michael")
True
>>> word = "Fred"
>>> word == ("John" or "Fred" or "Jim" or "Michael")
False
>>>
Instead, use a tuple or a set and the keyword in to check if word equals any of the four names:
>>> word = "John"
>>> word in {"John", "Fred", "Jim", "Michael"}
True
>>> word = "Fred"
>>> word in {"John", "Fred", "Jim", "Michael"}
True
>>>
>>> type({"John", "Fred", "Jim", "Michael"})
<type 'set'>
>>>
Finally, as Daniel pointed out, remember the colon, :, after function definitions such as def __init__(...)

Your code is throwing a NameError because at some point in the iteration of your file, some word variable doesn't fulfill any of the conditionals in this line of your function: if word == ("John" or "Fred" or "Jim" or "Michael"):, and name doesn't get defined.
The simplest way to workaround this error is to assign default values to your variables outside the scopes of your class and function (or within the scope of your function):
name = "name"
uni = "uni"
sex = "sex"
filename = "filename"
class resume:
# rest of your code
As an alternative, you could include conditional checks within your function for your variables; if the variable isn't yet defined, assign it a default value:
if "name" not in locals():
name = "name"
r = resume(name,uni,sex,filename)
Finally, you'll want to append a colon to this line, from this:
def __init__(self, name, uni, sex, filename)
to this:
def __init__(self, name, uni, sex, filename):
change this line where you intialize mylist from this:
mylist[]
to this:
mylist = []
and change:
mylist.insert(r)
to:
mylist.append(r)

Making a database with custom commands in python

I'm trying to make a simple, local database using Python where I can set values, get values, etc and I keep getting this error:
#Simple Database
#Functions include Set[name][value]
# Get[name]
# Unset[name]
# Numequalto[value]
# End
# Begin, Rollback, Commit
varlist = []
ops = []
class item:
def __init__(self,name,value):
self.name = name
self.value = value
class db:
def __init__(self):
self.varlist = []
self.ops = []
def Set(self,nm,val):
changed = False #Bool for keeping track of update
for item in varlist: #run through current list
if item.name == nm: #If the name is found
item.value = val #update the value
changed = True #found it
break #exit if found
if not changed:
newitem = item() #Create a new one and append it
newitem.name = nm
newitem.value = val
varlist.append(newitem)
def Get(key):
for item in varlist:
if item.name == key:
return item.value
break
def Unset(key):
for item in varlist:
if item.name == key:
item.value = -1
break
def Numequalto(key):
count = 0
for item in varlist:
if item.value == key:
count+=1
return count
def main():
newdb = db()
varlist=[]
comm = "" #prime it
while comm.lower() != "end":
comm = input("Command: ")
if comm.lower() == "begin":
print("----SESSION START---")
while comm.lower() != "end":
comm = input("Command: ")
part = []
for word in comm.split():
part.append(word.lower())
print(part)
if part[0].lower()=="set":
newdb.Set(part[1],part[2])
print(varlist)
elif part[0].lower()=="get":
gotten = Get(part[1])
print(gotten)
elif part[0].lower()=="unset":
Unset(part[1])
elif part[0].lower()=="numequalto":
numequal = Numequalto(part[1])
print(numequal)
print("Finished")
else:
print("--ERROR: Must BEGIN--")
if __name__ == "__main__":
main()
When I run this, and try to create a new item in my list using the command
set a 25
I get this error:
Traceback (most recent call last):
File "/Volumes/CON/LIFE/SimpleDatabase.py", line 81, in <module>
main()
File "/Volumes/CON/LIFE/SimpleDatabase.py", line 65, in main
newdb.Set(part[1],part[2])
File "/Volumes/CON/LIFE/SimpleDatabase.py", line 27, in Set
newitem = item() #Create a new one and append it
UnboundLocalError: local variable 'item' referenced before assignment
Any help would be much appreciated. I'm pretty new to Python

The line
for item in varlist:
shadows the class item with a local variable. So that when you get to your item() it thinks you are trying to call the local variable instead of the class. You can tell that your class item is never being constructed because it would fail as you are passing no parameters to the __init__
Also you should really call your class Item. Once I did that I got the constructor error as expected.

You have a few issues with your code:
You are shadowing the class item with a local variable of the same name.
You are using varlist instead of self.varlist.
Some of your class methods doesn't recieve a self first argument.
Also there is a strong convention in python to name classes with a first capital letter.

Not trying to be implite, just constructive here. I'm concerned that while there are comments questioning the intent to implement your own dictionary, no answer stated this forcefully. I say this only because part of Python (beyond the semantics, language, etc...) is the culture. We speak of things being 'Pythonic' for a reason - part of the value of this language is the culture. There are two aspects here to pay attention to - first, 'Batteries Included' and second, "Don't Reinvent the Wheel". You're reimplimenting the most fundamental composite (oxymoron, I know) data type in Python.
>>> a = {}
>>> a['bob'] = 1
>>> a['frank'] = 2
>>> a
{'frank': 2, 'bob': 1}
>>> del a['frank']
>>> a
{'bob': 1}
>>> del a['bob']
>>> a
{}
>>> a['george'] = 2
>>> b = len([x for x in a.values() if x == 2])
>>> b
1
And there you have it - the pythonic way of handling the functionality you're after.
If you're trying to add functionality or limitations beyond that, you're better off starting from the dict class and extending rather than rolling your own. Since Python is "duck-typed" there's a HUGE benefit to using the existing structure as your basis because it all falls into the same patterns.

Global Name Not Defined in Python

Am new to Python OOP. Please dont be harsh. Here is my code which calculates which is the fastest time of an athlete from a list and displays them. But When Running, I get this error:
z= add.mylist.min()
NameError: global name 'add' is not defined
My Code:
class Athlete:
def add(self):
list=[]
mylist=[]
for i in range(2):
self.name = raw_input("Enter name: ")
self.fastest_time = input("time: ")
list.append(self.name)
mylist.append(self.fastest_time)
print "Names: ",list
print "Fastest times: ",mylist
def display(self):
z= add.mylist.min()
w= add.mylist.index(z)
print "Minimum time: ",z
print "Name of athelte with fastest time: ",list[w]
x = Athlete()
x.add()
x.display()

You need to refer to methods on the instance with the self parameter. In addition, your add() method needs to return the mylist variable it generates, you cannot refer to method local variables as attributes on methods:
def display(self):
mylist = self.add()
z = min(mylist)
w = mylist.index(z)
def add(self):
list=[]
mylist=[]
for i in range(2):
self.name = raw_input("Enter name: ")
self.fastest_time = input("time: ")
list.append(self.name)
mylist.append(self.fastest_time)
print "Names: ",list
print "Fastest times: ",mylist
return mylist
That is what self is for, as a reference point to find instance attributes and other methods on the same object.
You may want to rename list to something that does not shadow the built-in type.

Martijn has already answered your question, so here are some remarks and code style tips:
New-style classes derive from object
You have both athlete names and their times, those belong together as key-value pairs in a dictionary instead of two separate lists
Don't use print statements inside class methods, a class method should return an object that you then can print
what if you have more then 2 athletes for which you want to enter the time? If you make the number of athletes an argument of your function, you can add a variable number of athlethes
give descriptive variable names (not mylist) and don't use names of builtin functions (like list) as variable name
variables that you want to use throughout your class can be initalized in an __init__method.
For printing, use the format function instead of using commas
use if __name__ == '__main__' so that your Python file can act as either reusable modules or as standalone program
Taking these into account, I would rewrite your code to something like this:
from collections import defaultdict
class Athlete(object): # see (1)
def __init__(self): # see (6)
self.athlete_times = defaultdict(str) # see (2)
def add_athletes_and_times(self, n): # see (4)
for i in range(n):
self.name = raw_input("Enter name: ")
self.fastest_time = input("time (in seconds): ")
self.athlete_times[self.fastest_time] = self.name
def get_fastest_time(self):
return min(self.athlete_times) # see (3)
if __name__ == '__main__': # see (8)
x = Athlete()
x.add_athletes_and_times(2)
for fast_time in x.athlete_times:
print "The fastest time of athlete {0} is {1} seconds.".format(
x.athlete_times[fast_time], fast_time) # see (7)
fastest_time = x.get_fastest_time()
print "The overall fastest time is: {0} seconds for athlete {1}.".format(
fastest_time, x.athlete_times[fastest_time])