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How to get an integer value from a 'for' loop in Python and print it

I am currently using Canopy to run my code. I was trying to fetch some integer data from the entry box in my GUI according to the number that I give in the for loop and print it. It is not working.

for

Here is the error:

Traceback (most recent call last):
File "C:Program FilesEnthoughtCanopyAppappdatacanopy-1.5.5.3123.win- x86_64liblib-tkTkinter.py", line 1532, in __call__
return self.func(*args)
File "C:UsersSIMULATORDesktoppythonlife cycle graphtry4.py", line 24, in const
z=int(s)
ValueError: invalid literal for int() with base 10: ''


My code is:

from Tkinter import *

root = Tk()

root.geometry('1000x600+400+400')

def const():

const_entries =

for i in range(0, 4):

en = Entry(root)
en.pack()
en.place(x=50, y = 200 + 25*i)

s = en.get()
z = int(s)

const_entries.append(z)

j = i + 1

label = Label(root, text="Alternative %r"%j)
label.pack()
label.place(x = 200, y = 200 + 25*i)

print const_entries

button1 = Button(root, text="Construction cost", command = const).grid(row = 15, column = 0)

root.mainloop()


z=int(s)

s

s=en.get()

TclError: cannot use geometry manager pack inside . which already has slaves managed by grid

4 Answers
4

Clarification: Assuming that s isn't empty (en.get() returns some number).

Check out this example:

s

en.get()

int('55.500000')

int('55.500000')

Gets you a: ValueError: invalid literal for int() with base 10: '55.500000'

ValueError: invalid literal for int() with base 10: '55.500000'

And:

float('55.500000')

float('55.500000')

Gets you:55.5

55.5

So just cast to float instead of int.

float

int

ValueError

s

As already stated in the other answers your code is failing because your entries are empty when you call the const method.

const

Assuming that you want to enter something in your entry boxes and then print the alternatives I guess a code like this would do the job:

from Tkinter import *

root=Tk()

root.geometry('1000x600+400+400')

def const():
const_entries =
for i in range(4):
s = entryArray[i].get()
z = int(s)
const_entries.append(z)

print const_entries

button1= Button(root,text="Construction cost", command = const).grid(row=15,column = 0)

entryArray =

for i in range(0,4):
entryArray.append(Entry(root))
#Insert default value 0
entryArray[i].insert(0, 0)
entryArray[i].pack()
entryArray[i].place(x=50,y=200+25*i)
label=Label(root,text="Alternative %d"%(i+1))
label.pack()
label.place(x=200,y=200+25*i)


root.mainloop()


This way you create the entries at startup and you give the user the time to enter something. When you press the Construction cost button the const function is called which will read the content of your entries and print them out.

Construction cost

const

Update
If you then want the user to enter the number of entries I'd suggest using a class and defining two buttons:

one for creating the entries after the user has entered the number

one for processing the number the user enters in the created entries

from Tkinter import *

root=Tk()

root.geometry('1000x600+400+400')

class MainWindow():
def __init__(self):
Label(root,text='Number of Entries').grid(row = 15, column = 0)
self.numEntry = Entry(root)
self.numEntry.grid(row = 15, column = 1)
self.numEntry.insert(0, 0)
Button(root,text="Build entries", command = self.buildEntries).grid(row = 15,column = 3)
Button(root,text="Construction cost", command = self.const).grid(row = 18,column = 0)

def buildEntries(self):
self.entryArray =
numEntries = int(self.numEntry.get())

for i in range(numEntries):
self.entryArray.append(Entry(root))
#Insert default value 0
self.entryArray[i].insert(0, 0)
self.entryArray[i].pack()
self.entryArray[i].place(x=50,y=200+25*i)
label=Label(root,text="Alternative %d"%(i+1))
label.pack()
label.place(x=200,y=200+25*i)

def const(self):
const_entries =
numVal = len(self.entryArray)
for i in range(numVal):
s = self.entryArray[i].get()
z = int(s)
const_entries.append(z)

print 'Const Entries:', const_entries



m = MainWindow()

root.mainloop()


When literal s couldn't be converted to int, int(s) failed.

s

int

int(s)

try:
z = int(s)
except ValueError:
z = 0


0

When you call en.get() at this point, it will return '' and then int('') will raise an error. Maybe before getting the integer you want to set an integer as string to the entry.

en.get()

''

int('')

entry

When you write button1 = Button(root, text="Construction cost", command = const).grid(row = 15, column = 0) button1 will not be a Button instance; button1 should be the result of the grid function.

button1 = Button(root, text="Construction cost", command = const).grid(row = 15, column = 0)

button1

Button

button1

grid

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