Python 3.3.2 tkinter ttk TreeView per-column sorting only sorts by last column?

Question

I am trying to get a simplistic ttk TreeView table going with per-column sorting using the heading 'command' tag, but it doesn't seem to work right. I'm using the answer to this question for implementing the functionality: Tk treeview column sort My code: ``` import tkinter as tk from tkinter import ttk def treeview_sort_column(tv, col, reverse): print('sorting %s!' % col) l = [(tv.set(k, col), k) for k in tv.get_children('')] l.sort(reverse=reverse) # rearrange items in sorted positions for index, (val, k) in enumerate(l): print('Moving Index:%r, Value:%r, k:%r' % (index, val, k)) tv.move(k, '', index) # reverse sort next time tv.heading(col, command=lambda: treeview_sort_column(tv, col, not reverse)) cols = ('name', 'path', 'time', 'pb') root = tk.Tk() root.geometry("700x500") listbox = ttk.Treeview(root, columns=cols, show="headings") for each in ('name', 'path', 'time','pb'): listbox.heading(each,text=each.capitalize(),command=lambda: treeview_sort_column(listbox, each, False)) li…

Accepted Answer

You should use lambda in other way. In your code every lambda gets a pointer to the same variable, that is why all functions do the same thing. You should, e.g, copy variable to make lambda unique. An example how to do it:

```
for each in ('name', 'path', 'time','pb'):
    listbox.heading(each,text=each.capitalize(),command=lambda each_=each: treeview_sort_column(listbox, each_, False))
```

Simple example:

```
funcs = []
for item in ('abc', 'def', 'ghi'):
    funcs.append(lambda : print(item))
for f in funcs:
    f()
```

It prints:

```
ghi
ghi
ghi
```

But version with fixed lambda:

```
funcs = []
for item in ('abc', 'def', 'ghi'):
    funcs.append(lambda item_=item: print(item_))
for f in funcs:
    f()
```

prints

```
abc
def
ghi
```

Python 3.3.2 tkinter ttk TreeView per-column sorting only sorts by last column?

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