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A sticky demonstration

As an aside, I am going to demonstrate what happens with the sticky parameters in Listing 4 when the column width changes. Compare Figure 4 with Figure 2

Figure 4 . A sticky demonstration.

Demonstrates effect of change in column width with sticky W, E

As you will see shortly, the numerical result of calculating the conversion from feet to meters is displayed in column 2 in the row immediately below the Entry widget. When that result requires more width than is available in the column by default, the width of the column is automatically increased.Because the right and left ends of the Entry widget stick to the sides of its cell in that column, the width of the Entry widget increases accordingly.

A Label and a Button

By now you should be catching on to the general scheme of things and less detailed instructions should be needed.

Listing 5 creates a Label widget and a Button widget and places them in the rows and columns indicated by the sticky parameters.

Listing 5 . A Label and a Button.
ttk.Label(mainframe, textvariable=meters).grid(column=2, row=2, sticky=(W, E)) ttk.Button(mainframe,text="Calculate", command=calculate).grid(column=3, row=3, sticky=W)

A few things are different here:

  • References to the widgets are not saved in ordinary Python variables because there will be no need to refer to them later in program code.
  • The dot operator is used to call grid immediately upon the creation of each widget as opposed to calling grid in a separate statement as was done in Listing 4 .
  • The Button widget uses a text argument to place the string "Calculate" on the face of the button.
  • No text is placed in the Label . The empty Label will be used to display the results of converting feet to meters.
  • The left end of the Button widget is stuck to the west side of the cell in which it resides. It is not stretched to the width ofthe cell as is the case with the Entry and Label widgets
  • Last and perhaps most important, the Button widget uses the command argument to specify that the function named calculate will be executed whenever the user presses the button.

Three more Label widgets

Listing 6 creates three more Label widgets and places them in the rows and columns shown.

Listing 6 . Three more Label widgets.
ttk.Label(mainframe, text="feet").grid(column=3, row=1, sticky=W) ttk.Label(mainframe, text="is equivalent to").grid(column=1, row=2, sticky=E)ttk.Label(mainframe, text="meters").grid(column=3, row=2, sticky=W)

There is nothing new in Listing 6 so no explanation of that code should be required.

Finishing touches

The author of the program describes the first line of code in Listing 7 as follows:

"The first line walks through all of the widgets that are children of our content frame, and adds a little bit of padding around each, so they aren't so scrunched together. We could have added these options to each "grid" call when we first put the widgets onscreen, but this is a nice shortcut."
Listing 7 . Finishing touches.
for child in mainframe.winfo_children(): child.grid_configure(padx=5, pady=5) feet_entry.focus()root.bind('<Return>', calculate)

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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Source:  OpenStax, Itse 1359 introduction to scripting languages: python. OpenStax CNX. Jan 22, 2016 Download for free at https://legacy.cnx.org/content/col11713/1.32
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