Code: Alles auswählen
# beispiel 1
def f1(x):
return x+1
def f2(x):
return f1(x)+1
print f2(1)
# beispiel 2
f1 = lambda x: x+1
def f2(x):
return f1(x)+1
print f2(1)
# beispiel 3
def f1(x):
return x+1
f2= lambda x: f1(x)+1
print f2(1)
# beispiel 4
f1 = lambda x: x+1
f2 = lambda x: f1(x)+1
print f2(1)
Ja. Es gibt absolut keine, weder bei der Definition noch der Ausführung.kommando_pimperlepim hat geschrieben:vielen dank für die schnelle antwort, Leonidas.
weiß jemand, ob es performanceunterschiede gibt?
wofür kann man das wirklich mal brauchen? Code: Alles auswählen
l = [("hello", 0), ("World", 1), ("world", 2), ("HELLo", -10)]
l.sort(key=lambda x: x[0].lower())
Code: Alles auswählen
l = [("hello", 0), ("World", 1), ("world", 2), ("HELLo", -10)]
def keyfunc(x):
return x[0].lower()
l.sort(key=keyfunc)
Code: Alles auswählen
class ClassTKWINDOW:
def __init__(self,master):
self.but = Button(master, text="test", command=lambda: textmalen('hallo welt'))
self.but.pack()
Code: Alles auswählen
class ClassTKWINDOW:
def __init__(self,master):
def callback():
textmalen('hallo welt')
self.but = Button(master, text="test", command=callback)
self.but.pack()
Davon abgesehen sieht man ``lambda``s hauptsächlich in Tkinter. In anderen Toolkits kann man Callback-Funktionen Parameter mitgeben, bzw. die wichtigsten Parameter werden implizit mitgegeben.Sr4l hat geschrieben:ach die möglichkeit hatte ich vergessen man kann ja funktionen in funktionen schreiben und diese funktionen haben zugriff auf die variablen.
Code: Alles auswählen
def label_button_row(self, parent_widget=None,
btnlst=None, start_count=0):
"""Build a 2 column table with a label beside each button in a row.
Bind a keyboard sequence to the button command.
Display this keyboard sequence on the label.
todo:
- think about a parameter for the widget to bind the Hotkeys
- rename to: labled_button_row, draw_labled_button_row
Parameter:
--> parent_widget:
Parent widget to place the table
--> btnlst:
Type: List of dicts representing a button
Example:
{'text':'**bold**', # displayed on the Button (string)
'cmd':self.on_tag_insert, # command
'open_tag':'**', # chars representing the beginning
# of a tag for inserting (string)
'close_tag':'**', # chars representing the end
# of a tag for inserting (string)
'keytxt':'CTRL+b', # displayed on the Label (string)
'hotkey':'<Control-b>'} # keyboard sequence (string)
Note:
The existence of 'open_tag' and 'close_tag' in btnlst
decides which command is bound to the Button.
If they aren't there 'cmd' must be a function without
parameters!!!
otherwise 'cmd' needs following parameters:
otag = btn['open_tag']
ctag = btn['close_tag']
event = None # Placeholder for a keysequence
--> start_count:
Type: int
Description:
The table is relized with tkinter grid layout manager.
start_count is used if there is already a grid
(with a Label beside a button).
start_count can add the automatic genrated
buttons under the existing.
In Wombat_Editor it is used to put a label_button_row
under a Tkinter menubutton(file choose, headlines).
"""
i = start_count
for btn in btnlst:
try:
otag = btn['open_tag']
ctag = btn['close_tag']
event = None
doit = lambda e=event, o=otag, c=ctag:self.on_tag_insert(e,o,c)
tk.Button(parent_widget, text=btn['text'], command=doit,
relief=tk.RIDGE
).grid(column=0, row=i, sticky=tk.W+tk.E)
self.text.bind(btn['hotkey'],doit)
except KeyError:
# generate buttons with an unique command for every button
tk.Button(parent_widget, text=btn['text'], command=btn['cmd'],
relief=tk.RIDGE
).grid(column=0, row=i, sticky=tk.W+tk.E)
tk.Label(parent_widget, text=btn['keytxt'], relief=tk.FLAT
).grid(column=1, row=i, sticky=tk.W)
i +=1