Swapping lines in a Tkinter text widget

Question

I Have everything set up, I just can't figure out how to swap 2 lines in a Tkinter text widget. It's disabled and populated by other widgets so I gave the disabled/unfocused text widget some functionality with 3 buttons; Move_Up, Move_Down, and Delete. I have delete working but can't figure out how to get the other two to work. Right now i'm working with 2 values that reference the start and end of the line of text that is going to be modified: self.line_start and self.line_end

And here's what I have so far:

def Move_Up(self):
   self.TextWidg.config(state='normal')
   #swap this line with the line above it
   self.TextWidg.config(state='disabled')

def Move_Down(self):
   self.TextWidg.config(state='normal')
   #swap this line with the line below it
   self.TextWidg.config(state='disabled')

def Delete(self):
   self.TextWidg.config(state='normal')
   #delete the line
   self.TextWidg.delete(self.line_start,self.line_end)
   #delete the carriage return
   self.TextWidg.delete(self.line_start)
   self.TextWidg.config(state='disabled')

Basically, how would I implement my values of self.line_start and self.line_end to swap the line with the line before it or the line after it.

Answer 1

Following Bryan's suggestions, I was able to solve the Move_Up() and Move_Down() methods as follows. It works using Python 3.1.3 or 2.6.6 on Mac OS X.

#swap this line with the line above it
def Move_Up():
    text.config(state='normal')
    # get text on current and previous lines
    lineText = text.get("insert linestart", "insert lineend")
    prevLineText = text.get("insert linestart -1 line", "insert -1 line lineend")

    # delete the old lines
    text.delete("insert linestart -1 line", "insert -1 line lineend")
    text.delete("insert linestart", "insert lineend")

    # insert lines in swapped order
    text.insert("insert linestart -1 line", lineText)
    text.insert("insert linestart", prevLineText)
    #text.config(state='disabled')


#swap this line with the line below it
def Move_Down():
    text.config(state='normal')
    # get text on current and next lines
    lineText = text.get("insert linestart", "insert lineend")
    nextLineText = text.get("insert +1 line linestart", "insert +1 line lineend")

    # delete text on current and next lines
    text.delete("insert linestart", "insert lineend")
    text.delete("insert +1 line linestart", "insert +1 line lineend")

    # insert text in swapped order
    text.insert("insert linestart", nextLineText) 
    text.insert("insert linestart + 1 line", lineText)
    #text.config(state='disabled')

EDIT: Note that it if there is only one line of text Move_Up() will append that text to that line. And Move_Down() does nothing if there is only one line.

Answer 2

You can get the index of any position in the widget with the index method. You can give it an argument that includes modifiers such as linestart and lineend . You can also get the index of a relative position with something like +1c to get the index of the next character, or +1l to get the next line. You can also use wordstart and wordend . You can combine them, for example: index("insert lineend +1c")

For example, to get the start and end of the line that has the insertion cursor (where 'insert' is the name of the mark that represents the insertion cursor):

start = self.TextWidg("insert linestart")
end = self.TextWidg("insert lineend")

For more information, see the section titled "expressions" on the text widget page on effbot.org .

Answer 3

text.delete("insert linestart +0 line","insert +0 line lineend") Move_down delete