I'm working on a school project. I made a test version of my program, because I'm new to Python and I only have experience with C#, so I'm still learning te basics. My problem is the following:
Before the function "Fill_Array()" I declared a variable (" max_element_var") that is supposed to store the max number of elements that can be stored in the array ("content_array"). Later in the function I change it's value to the input of the console, which happens, and the function runs as it should, the only problem being is that outside the function the value of " max_element_var" stays "None". What should I do in order to fix this?
#__Test__#
def Test():
class Que:
def __init__(self, content, max_element ,actual_elements):
self.content = content
self.max_element = max_element
self.actual_elements = actual_elements
max_element_var = None
content_array = []
def Fill_array():
print("What should be the max number of elements that can be stored in the array? (Type in an integer!)")
max_element_var = int(input())
if(max_element_var>0):
import random
random_var = random.randrange(0,max_element_var)
for x in range(max_element_var-random_var):
content_array.append(x)
else:
print("It has to be more than 0!")
Fill_array()
Fill_array()
actual_elements_var = len(content_array)
que = Que (content_array, max_element_var, actual_elements_var)
print("Content: ", que.content)
print("Max number of elements: ", que.max_element)
print("Actual number of elements: ", que.actual_elements)
#__Test__#
#__Full__#
def Full():
pass
#__Full__#
#__Version_selector__#
def Version_selector():
print("Which version should be used? (Type in the number!)")
print("1 - Test")
print("2 - Full")
answer = int(input())
if(answer == 1):
Test()
Version_selector()
elif(answer == 2):
Full()
Version_selector()
#__Version_selector__#
Version_selector()
In python variables are automatically created as local, in the scope of the function which used them alone.
To solve your problem you may either
(1) return the variable, passing it from one function the other explicitly.
(2) declare it as global so all functions have access to it.
More about scopes here and here.
Consider the following code. In the code below you persumably change the value of x but in fact there is a big difference between the x inside the function and outside. The x inside the function is a local variable and will "disappear" once the function ends. If you want to save the value of x you must use return x and save the outcome to a variable. For example, See the function a_saving_example(x)
you may also use a global variable though some say it is bad practice and it is better to use return in your function.
def times_two(x):
x = x * 2
x = 5
print(x)
times_two(x)
print(x)
output:
5
5
saving example:
def a_saving_example(x):
x = x * 2
return x
x = 5
print(x)
x = a_saving_example(x)
print(x)
output:
5
10
Modified code to correct some issues.
Import normally done at top of module (not within functions)
Remove nested class definition inside function (obfuscates things in simple code)
Changed recursive calls to a while loop (a better way to repeat execution of a function from beginning in Python since no tail recursion).
Code Refactoring
import random
class Que:
def __init__(self, content, max_element ,actual_elements):
self.content = content
self.max_element = max_element
self.actual_elements = actual_elements
def Fill_array():
" Returns requested size and array "
while True:
prompt = """"What should be the max number of elements that can be stored in the array? Type in an integer!: """
max_element_var = int(input(prompt))
if max_element_var > 0:
random_var = random.randrange(0,max_element_var)
return max_element_var, [x for x in range(max_element_var-random_var)]
else:
print("It has to be more than 0!")
def Test():
max_element_var, content_array = Fill_array()
actual_elements_var = len(content_array)
que = Que (content_array, max_element_var, actual_elements_var)
print("Content: ", que.content)
print("Max number of elements: ", que.max_element)
print("Actual number of elements: ", que.actual_elements)
#__Test__#
#__Full__#
def Full():
pass
#__Full__#
#__Version_selector__#
def Version_selector():
while True:
prompt = """Which version should be used? (Type in the number!)
1 - Test
2 - Full
3 - Quit\n\t"""
answer = int(input(prompt))
if answer == 1:
Test()
elif answer == 2:
Full()
else:
break
#__Version_selector__#
Version_selector()
Related
I have a program that I want to be able to print all of the instances of each variable using my method that I created. Problem is I can't figure out a way to print them since each are listed under a different variable that aren't configured from hardcoding them in and I need a way to automatically recall them in my code.
class fit:
def __init__(self,day,did,workout='Not Recorded',time='An unknown amount of',calories='An unknown amount of'):
self.day = day
self.did = did
if did.lower()=='no':
self.workout = 'Not Recorded'
self.time = "An unknown amount of Minutes"
self.calories = "An unknown amount of Calories"
else:
self.workout = workout
self.time = "{} Minutes".format(time)
self.calories = "{} Calories".format(calories)
def formate(self):
self.formate = "{}:\n\nDid you work out: {}\nWorkout focus: {}\nYou worked out for: {}\nYou burned: {}\n\n----------------------------------------------------------".format(self.day,self.did,self.workout,self.time,self.calories)
return self.formate
def reader(day,index):
file = open('readme.txt')
file = file.read()
stripped = file.rsplit("\n")
for i in range(len(stripped)):
stripped[i] = stripped[i].rsplit(" ")
del stripped[-1]
if int(index) >= len(stripped[day-1]):
return "none"
else:
return stripped[day-1][index]
x = 0
def create_new_instance(class_name,instance_name):
globals()[instance_name] = class_name(reader(x,0),reader(x,1),reader(x,2),reader(x,3),reader(x,4))
print('Class instance {} created'.format(instance_name))
while True:
try:
x+=1
ins = 'day_' + str(x)
create_new_instance(fit,ins)
except:
break
break
def printer(instance):
print(.formate())
while True:
x+=1
inst = 'day_' + str(x)
printer(inst)
An example of this might be that I have 8 lines of data from a text document and I have a system that creates instances of day_1, day_2, day_3 ect until day_8 and then I want to print each of those instances out, but again I don't have those instances directly hardcoded into my code so I don't know how I'd do it. I've tried looking into maybe a while loop and increasing a variable by 1 and concatenating it with day and trying to make a variable out of that but the my limited experience with python isn't helping.
A very unpythonic and ugly way would be to use exec, for example:
day_3=5
x = 'day_'+'3'
exec("print("+x+")")
I would recommend another way to store your variables though.
Hi for a given function I have 2 parameters which are string and an Int but I don't know which comes first. So I have a function "pick_type()" that tries to guess the order of the parameters. So my question is when "pick_type()" incorrectly guesses the order, how do I record this and make sure "pick_type()" never tries that specific order again ?
for iteration in range(0, 10):
args = []
print("\n def test%d(self):" % (iteration))
for input in range(num_arguments):
args += pick_type()
try:
result = target(*args)
code = test_to_string(target, args, result)
except TypeError as error:
code = test_to_string_exc(target, args, error)
for line in code.splitlines():
print(" "+line)
def pick_type():
lista = []
words = ['rhythms', 'rhythms', 'manager', 'training', 'hotel', 'destroy']
word = choice(words)
num = random.randint(-100, 100)
lists = [word,num]
choices = choice(lists)
if choices == word:
lista.append(word)
else:
lista.append(num)
return lista
I would suggest wrapping your method in a class, then you can have a persistent list of bad orders. It's not clear to me what you mean by an "order", but whatever it is, hopefully this pseudo-code helps:
class PickType:
def __init__(self):
self._bad_orders = []
def pick_type(self):
...# insert body here
if order in self._bad_orders:
## pick another order
## test the new order
if <order is bad>:
self._bad_orders.append(order)
## if your test for bad orders is performed outside pick_type(), you just need a method to add to the list of bad_orders
def add_bad_order(self, order):
self._bad_orders.append(order)
Hi I'm a beginner programmer. I don't know how can I call a variable from function.
I have two def calcular() and guardar(). I get some variables from calcular() that I will call later, but when I call variables in guardar(), it tells me that variable is not defined. I tried making global var, but it doesn't work. Hope you can help me
This is a little of my code...
def calcular():
if nClient == "":
texto = ("Inserta Numero de cliente")
ventanaMensaje(texto)
else:
if cl1=="":
texto = ("Inserta Clave")
ventanaMensaje(texto)
else:
if aB1 == "":
texto = ("Inserta Cantidad")
ventanaMensaje(texto)
else:
try:
clt = open("preciosEsp.txt","r+")
lClt = clt.readlines()
rClt = lClt[0]
sClt = rClt.split("'")
nRClt = sClt[0]
if nClient == nRClt:
cReg=sClt[1]
if cl1== cReg:
prc=sClt[2]
else:
k=1
while cl1 != cReg:
cReg=sClt[k]
k=k+2
if cl1== cReg:
ñ=k-1
prc=sClt[ñ]
else:
x = 0
while nClient != nRClt:
rClt = lClt[x]
sClt = rClt.split("'")
nRClt = sClt[0]
x=x+1
if nClient == nRClt:
cReg=sClt[1]
if cl1==cReg:
prc=sClt[2]
else:
k=1
while cl1 != cReg:
cReg=sClt[k]
k=k+2
if cl1== cReg:
ñ=k-1
prc=sClt[ñ]
indice=int(prc)+3
pdcts = open("productos.txt","r+")
lPdcts = pdcts.readlines()
rPdcts = lPdcts[0]
sPdcts= rPdcts.split("'")
nPdcts = sPdcts[0]
t = 0
if cl1 == nPdcts:
precio1=sPdcts[indice]
global txtD1################## MAKE A GLOBAL VAR
txtD1=sPdcts[1] #### THIS IS THE VARIABLE ########
def guardar():
guardarDatos = (n+txtD1) ################# I CALL HERE, BUT TELL ME THAT VARIABLE IS NOT DEFINED
If you really want a global variable, you'd define it outside of any function
txtD1 = None
def calcular():
...
it will then exist at module level. However, globals are rarely (read: never) the solution you should be using, instead you should be returning information from functions rather than modifying global state. You'd then pass that information into another function to use.
The global keyword in python says that you are referencing a global variable, not creating a new one. However, in your code no such name exists, so you're not actually referencing anything.
first create your "database" somewhere global
clt = dict(map(lambda x:x.split(" ",1),open("preciosEsp.txt","r+"))
now you can acess it anywhere with
clt.get(nClient)
next calcular should return the values you want
def calcular():
...
precio = clt.get(nClient)
return [precio,nClient,...]
then you would store the returned values (or do something with them as soon as they are returned )
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])
I am trying to set a new variable to reference a variable inside a function. My pseudo code goes like this:
def myfunction():
a bunch of stuff that results in
myvariable = "Some Text"
Further down the code I have this:
for something in somethinglist:
if something == iteminsomethinglist:
myfunction()
mynewvariable1 = myvariable
elif something == iteminsomethinglist:
myfunction()
mynewvariable2 = myvariable
else:
mynewvariable3 = myvariable
I keep getting an error message that says something like: name 'myvariable' is not defined
I guess I thought that if I called the function, it processes some stuff, I pass result into a variable and then reference that variable to a more unique variable, it would store it....but it's not.
Edit: I am attaching my code because it I wasn't clear enough in my first post. There is a variable within my function I wanted to reference outside of it (actually there are 2) I apologize for not making it clear enough. I though my original psuedo code proposed the question well enough. I also have a feeling that this might not be the best approach. Possible calling 2 functions would be more appropriate? My code is below:
def datetypedetector():
rows = arcpy.SearchCursor(fc)
dateList = []
for row in rows:
dateList.append(row.getValue("DATE_OBSERVATION").strftime('%m-%d-%Y'))
del row, rows
newList = sorted(list(set(dateList)))
dates = [datetime.strptime(d, "%m-%d-%Y") for d in newList]
date_ints = set([d.toordinal() for d in dates])
if len(date_ints) == 1:
DTYPE = "Single Date"
#print "Single Date"
elif max(date_ints) - min(date_ints) == len(date_ints) - 1:
DTYPE = "Range of Dates"
#print "Range of Dates"
else:
DTYPE = "Multiple Dates"
#print "Multiple Dates"
fcList = arcpy.ListFeatureClasses()
for fc in fcList:
if fc == "SO_SOIL_P" or fc == "AS_ECOSITE_P":
datetypedetector()
ssDate = newList
print fc + " = " + str(ssDate)
ssDatetype = DTYPE
print ssDatetype
elif fc == "VE_WEED_P":
datetypedetector()
vwDate = newList
print fc + " = " + str(vwDate)
vwDatetype = DTYPE
print vwDatetype
else:
datetypedetector()
vrDate = newList
print fc + " = " + str(vrDate)
vrDatetype = DTYPE
print vrDatetype
As written, myvariable is only defined within the scope of myfunction.
To make the value in that variable available outside of the function you can return it from the function:
def myfunction():
myvariable = "Some Text"
return myvariable
And then use it later like this:
for something in somethinglist:
if something == iteminsomethinglist:
mynewvariable1 = myfunction()
Edit: new information added to question.
Your indentation seems slightly off, but that may just be copy-paste trouble.
I think what you want to do is something like this:
Call the datetypedetector function taking fc as an argument.
Return DTYPE from that function for later use.
So first change the function signature to:
def datetypedetector(fc):
^^
And the final statement in datetypedetector to:
return DTYPE
And then pass fc as an argument when you call it, and the final step is to get the DTYPE back from the function by assigning to it datetypedetector's return value.
for fc in fcList:
if fc == "SO_SOIL_P" or fc == "AS_ECOSITE_P":
DTYPE = datetypedetector(fc)
...
A much better way to organize the code would be to do something like this:
def myfunction():
return "Some Text"
for something in somethinglist:
if something == iteminsomethinglist:
mynewvariable1 = myfunction()
elif something == iteminsomethinglist:
mynewvariable2 = myfunction()
else:
mynewvariable3 = myfunction()