Develop Reference

Passing a variable as a list of arguments

My code is below. I'm just getting the basic functionality working before making more of the database, but I've run into a problem - Is there any way to pass a variable into four different arguments? My create_person function uses four arguments, but I need to initiate this after I create a Person object.
import os
import sqlite3
from personClass import *
#Connection to database - ToDoDB.db
conn = sqlite3.connect('ToDoDB.db')
cursor = conn.cursor()
def create_table_ToDo():
cursor.execute("""CREATE TABLE ToDo (
Forename text,
Surname text,
FirstChore text,
SecondChore text
)""")
print("ToDo table successfuly created!")
conn.commit()
def create_person(Forename, Surname, FirstChore, SecondChore):
query= "INSERT INTO ToDo (Forename, Surname, FirstChore, SecondChore)values (?,?,?,?);" #Inserts values below into this - question mark to sanitize first -
cursor.execute(query,(Forename, Surname, FirstChore, SecondChore)) #- then executes this command
conn.commit() #Commit and close after each function to save
print("New person and tasks added to the list of users")
#create_table_ToDo()
johnTest = Person("John", "Test", "Ironing clothes", "Washing dishes")
print(johnTest)
create_person(johnTest)
I've included my person class here just in case it helps.
class Person(ToDo):
def __init__(self, firstName, lastName, choreOne, choreTwo):
super().__init__(choreOne, choreTwo)
self.firstName = firstName
self.lastName = lastName
def getName(self):
print("My name is " + self.firstName + " " + self.lastName)
def getTasks(self):
print("My name's " + self.firstName + " and my tasks are " + self.choreOne + ", " + self.choreTwo)
def __repr__(self):
response = "{},{},{},{}".format(
self.firstName,
self.lastName,
self.choreOne,
self.choreTwo)
return response

You can use python's built-in getattr method to access the attribute values of an object. The following line should work:
create_person(getattr(johnTest, 'firstName'), getattr(johnTest, 'lastName'), getattr(johnTest, 'choreOne'), getattr(johnTest, 'choreTwo'))

How to make a function that calls aand prints each students name and courses

Here is what i have so far
from CSE_324_course import Course
from CSE_324_skeleton_student import Student
math = Course("Algebra I")
language = Course("Spanish I")
science = Course("Earth Science")
history = Course("U.S. History I")
phys_ed = Course("Physical Education I")
speaking = Course("Speech I")
art = Course("Art I")
test_student = Student("Jill", "Sample")
test_student.add_course(math)
test_student.add_course(language)
test_student.add_course(science)
test_student.add_course(history)
test_student2 = Student("Bill", "Sample")
test_student2.add_course(math)
test_student2.add_course(phys_ed)
test_student2.add_course(science)
test_student2.add_course(history)
test_student3 = Student("Kim", "Sample")
test_student3.add_course(language)
test_student3.add_course(speaking)
test_student3.add_course(science)
test_student3.add_course(art)
student_list=[test_student,test_student2,test_student3]
for (test_student,test_student2,test_student3 : get_course)
if (test_student().equals(search))
System.out.println(teststudnetgetCourse());
#Each iteration should:
#get,concatenate, and print the first and last name of the student
#print all courses for that student
#print a blank line between students
'''for this part you may need to review the other skeleton code to:
- see how to get items from a list
- see if there is code (like a function) in that file you can call in this file
- verify that running this file gets you the correct output with information from that file
Also, review syntax of pulling items from a list f
2 page of code
Course import Course
class Student:
student_id = 0
def __init__(self, first_name, last_name):
self.first_name = first_name
self.last_name = last_name
self.courses = []
self.student_id = Student.student_id
Student.student_id += 1
def __str__(self):
# TODO You will need to use a variable in the loop, so you must intialize it here,
# that variable will need to be initalized to get items listed in the first def _init_ section
# TODO add a loop that will go through the course list
# TODO Add code here to create a string representation of a student,
# including first and last name and all courses that student is taking
return "complete this return statement based on your in loop variable"
def get_first_name(self):
return self.first_name
def get_last_name(self):
return self.last_name
def get_student_id(self):
return self.student_id
def add_course(self, new_course):
# TODO add code to append new_course to self.courses
print "Course not yet added, implementation needed."
3rd page
class Course:
def __init__(self, course_name):
self.course_name = course_name
def __str__(self):
return self.course_name

I think you are looking to change
for (test_student,test_student2,test_student3 : get_course)
if (test_student().equals(search))
System.out.println(teststudnetgetCourse());
(which you have improperly indented) to:
for student in student_list:
print("{} {}".format(student.first_name, student.last_name))
for course in student.courses:
print(course) # This won't work because "2 page of code Course import Course" needs to be finished
print("\n") # blank line between students

AttributeError when calling instance method I defined

I coded this in python 3 and it is showing an attribute error.code is
as following:
import datetime
class MessageUser():
User_Details = []
Messages = []
base_message = """Hi {name}!
Thank you for the purchase on {date}.
We hope you are exicted about using it. Just as a
reminder the purcase total was ${total}.
Have a great time!
from Pritom_Mazhi
"""
def add_user(self, name, amount, email=None):
name = name[0].upper() + name[1:].lower() #Capitalizing the first letter of all names - formatted name
amount = "%.2f" %(amount) #formatted amount
detail = {
"name" : name,
"amount" : amount,
}
today = datetime.date.today()
date_text = '{tday.day}/{tday.month}/{tday.year}'.format(tday=today) #formatted date
detail["date"] = date_text
if email is not None:
detail["email"] = email
self.User_Details.append(detail)
def get_details(self):
return self.User_Details
def make_message(self):
if len(self.User_Details) > 0:
for detail in self.get_details(): #for detail in self.User_Details
name = detail["name"]
amount = detail["amount"]
date = detail["date"]
email = detail["email"]
message = self.base_message
formatted_message = message.format(
name = name,
total = amount,
date = date,
)
self.Messages.append(formatted_message)
return self.Messages
else:
return []
obj = MessageUser()
obj.add_user("Pritom", 123.32, email='hello#teamcfe.com')
obj.add_user("jon Snow", 94.23)
obj.add_user("Sean", 93.23)
obj.add_user("Emilee", 193.23)
obj.add_user("Marie", 13.23)
obj.get_details()
obj.make_message()
when i run it i get this error:
File "Class_StringFormat.py", line 57, in <module>
obj.get_details()
AttributeError: 'MessageUser' object has no attribute 'get_details'
i simply can't find what wrong i did there and so can't manage to fix it.

If your indentation is reproduced correctly in the question, get_details is defined inside add_user and is not visible from outside.
You should unindent the definition of get_details and make_message to be on the same level as add_user:
def add_user(self, name, amount, email=None):
# method body...
def get_details(self):
return self.User_Details
def make_message(self):
# method body

Taking list of elements as param in Class method

I have a class Dbcrud() that I will outline below.
I want to take several parameters from a method: db_select() one being selected_fields which would be a list of fields.
Im having trouble forming my method db_select() to allow multiple fields to be defined for selected_fields.
Can someone help?
Thank you
UPDATED
class DbCrud:
query_stmt_list = ['SELECT','INSERT','UPDATE','DELETE','FROM','WHERE']
def __init__(self):
self.query_stmt_list = DbCrud.query_stmt_list
self.query_stmt_list = query_stmt_list
def set_db_settings(self, host, username, passwd, database):
self.host = host
self.username = username
self.passwd = passwd
self.database = database
db = pymysql.connect(host=host, user=username, passwd=passwd, db=database)
return db
def db_select(self, selected_fields, table, where_field):
self.selected_fields = selected_fields
self.table = table
self.where_field = where_field
try:
with db.cursor() as cursor:
sql_tld_id_query = self.query_stmt_list[0] + selected_fields* + self.query_stmt_list[4] + table + self.query_stmt_list[5] + where_field + '=' + %s
cursor.execute(sql_tld_id_query, (self.site_search_url,))
tld_id_value = cursor.fetchone()
except:
db.rollback()
pass

You have few issues here:
1.
You need that row at the init method (as this is the c'tor of the class)
Also as query_stmt_list is a static member, you should access him with the class name as prefix.
def __init__(self):
self.query_stmt_list = DbCrud.query_stmt_list
2.
You can't define a function param with selected_fields[], it's a syntax error, you can pass to selected_fields whatever you like.
def db_select(self, selected_fields, table, where_field):
3.
When you try to use the variable query_stmt_list (at the following line of code i've attached), do you mean you want the class member or the instance member?
If instance you should change it to self.query_stmt_list
If the class member, you should change it to DbCrud.query_stmt_list
sql_tld_id_query = query_stmt_list[0] + selected_fields* + query_stmt_list[4] + table + query_stmt_list[5] + where_field + '=' + %s
Also, in order to loop though the selected_fields you could do:
query_stmt_list[0] + ", ".join(item for item in self.selected_fields) + query_stmt_list[4] ...

You can always expect selected_fields to be a list so you can use ', '.join:
def db_select(self, selected_fields, table, where_field):
query = 'select {selected_fields} {table} where {where_field} = 1'
query = query.format(selected_fields=', '.join(selected_fields),
table=table, where_field=where_field)
.
.
obj.db_select(['col_a'], 'table_a', 'where_field_a')
Note that this is vulnerable to SQL injection, but so is your original code (if it wasn't for the syntax errors it currently has).

strange python 2.7 dict behavior: key not inside while clearly there

I have written a Parser that takes a JSON configuration and creates objects from it. I first create a well known object, and try to dynamically import a module (which may be from a user), while loading its class via the defined creator method of that module.
Here is some testing code:
import json
import imp
import os.path as path
from lib.config.members import Member
from lib.tasks.task import Task
class Parser(object):
def __init__(self):
self._loadedMods = {"tasks": {}}
def _load_module(self, clazz, modPart):
"""
imports and caches a module.
:param clazz: the filename of the module (i.e email, ping...)
:param modPart: the folder of the module. (i.e services, parsers...)
:return: the imported/cached module, or throws an error if it couldn't find it
"""
mods = self._loadedMods[modPart]
if clazz in mods:
return mods["class"]
else:
#mod = __import__(clazz)
p = path.join("lib", modPart, clazz + ".py")
mod = imp.load_source(clazz, p)
mods[clazz] = mod
return mod
def replace_with_import(self, objList, modPart, items_func, class_check):
"""
replaces configuration dicts with their objects by importing and creating it in the first step.
In the second step the original list of json config dicts gets replaced by the loaded objects
:param objList: the list of objects which is iterated on
:param modPart: the folder from the module (i.e tasks, parsers)
:param items_func: function to get a pointer on the list of json-config-objects to replace. Takes one argument and
should return a list of
:param class_check: currently unsupported
"""
for obj in objList:
repl = []
items = items_func(obj)
for clazzItem in items:
try:
clazz = clazzItem["class"]
mod = self._load_module(clazz, modPart)
item = mod.create(clazzItem)
if class_check(item):
repl.append(item)
else:
print " ignoring class " + clazzItem["class"] + "! It does not pass the class check!"
except ImportError, err:
print "could not import " + clazz + ": " + str(clazzItem) + "! reason:"
print str(err)
except KeyError, k:
print "Key " + str(k) + " not in classItem " + str(clazzItem)
except Exception, e:
print "Error while replacing class ( " + clazz + " :" + str(e) + ")"
del items[:]
items.extend(repl)
def _create_raw_Object(self, jsonDict, msgName, creator):
"""
creates an Main object from the configuration, but just parses raw data and hands it to the object
:param jsonDict: the configuration file part as dict
:param msgName: name of object for error message
:param creator: function pointer which is taking two arguments: identifier of the object and arguments.
:should return an object
:return: a list of objects returned by creator
"""
items = []
for key, val in jsonDict.items():
try:
item = creator(key, val)
items.append(item)
except Exception, e:
print "ignoring " + msgName + ": " + key + "! reason:"
print str(e)
return items
jsonFile = '''
{
"members":{
"homer":{
"name": "Homer Simpson",
"comment": "Security Inspector",
"tasks": [{"class":"email", "type": "donut", "args": {"rcpt": "homer_j_simpson#burnscorp.sp"}},
{"class":"email", "type": "do", "args": {"rcpt": "my_other_mail#burnscorp.sp"}}]
}
}
}
'''
jsonDict = json.loads(jsonFile)
parser = Parser()
creator = lambda name, values: Member(name, **values)
members = parser._create_raw_Object(jsonDict["members"], "Members", creator)
items_func = lambda member: member.get_tasks()
class_check = lambda task: isinstance(task, Task)
parser.replace_with_import(members, "tasks", items_func, class_check)
for d in members:
print d.__dict__
As you can see, a Member can have a list of arbitary tasks, and which one it should import is defined in its class attribute, but as soon as two of them has the same value for the class (which shouldn't break json the way we define it) I get a strange KeyError :
Key 'class' not in classItem {u'args': {u'rcpt': u'my_other_mail#burnscorp.sp'}, u'type': u'do', u'class': u'email'}
Why do I get this strange error? Any hint that my give me a clue whats going on is very welcome, as I feel hopeless, debugging this for hours.
I think that Member and Email/Task class are unrelated but Ill post them for completeness:
lib/config/members.py
class Member:
def __init__(self, id, name="", comment="", tasks=None):
self.id = id
self.name = name
self.tasks = []
self.add_task(tasks)
self.comment = comment
def get_id(self):
return self.id
def add_task(self, task):
if task is None:
return
if isinstance(task, list):
self.tasks.extend(task)
else:
self.tasks.append(task)
def get_tasks(self):
return self.tasks
lib/tasks/[task|email].py
class Task:
"""
Base class for all built-in Tasks.
"""
def set_task_type(self, taskType):
"""
sets the type of this task.
Be aware! this method can only get called once!
:param taskType: the type of this task
"""
if hasattr(self, "_taskType"):
raise Exception("taskType is only allowed to set once!")
self.taskType = taskType
def get_task_type(self):
"""
:return: the type set by set_type_task
"""
return self._taskType
"""
The email task.
"""
from lib.tasks.task import Task
class EmailTask(Task):
def __init__(self, **kwargs):
self.set_task_type(kwargs["type"])
self.recipient = kwargs["args"]["rcpt"]
def execute_task(self, msg):
pass
def create(taskDict):
return EmailTask(**taskDict)

It seems you are eating the actual exception by replacing it with your own custom print in replace_with_import. As I noted in the comment section.
You generally want to keep you try blocks small and very predictable, knowing exactly what can be raised and what you should handle at that point in the code. The less complexity in your try block the better.