Say, for example, in tkinter, someone created a function corresponding to each of the 26 letters of the English alphabet. Then, he/she wants to be able to take a string provided by the user, make all the uppercase letters lowercase, and then execute the function(s) corresponding to each letter of the string. Here is a pseudocode example of what I am talking about:
# The functions should draw, on a tkinter canvas, the letter each function corresponds to (a pseudocode example shown below):
a -> draw_a
b -> draw_b
c -> draw_c
d -> draw_d
# So on, so forth...
str = input('Enter a string please: ').lower()
for i in str:
if i is # a letter:
# execute function corresponding to current letter in string
else:
pass # If current character is not a letter
Is it possible to do this in Python? If so, how would I implement this ability?
Use a dictionary to map letters to functions:
def draw_a(): # ...
def draw_b(): # ...
per_letter = {
'a': draw_a, 'b': draw_b, # ...
}
for char in string:
if char.isalpha():
per_letter[char]()
Note that the function object is put in the dictionary, they are not called, not until we look them up in the dictionary with per_letter[char]
.
I assume you want the following:
If you have an 'a', call function draw_a
In that case you can use:
letter='a'
locals()["draw_"+letter]()
or, in your case:
for i in str:
if i is # a letter:
locals()["draw_"+i]()
else:
pass # If current character is not a letter
locals()
is a dict containing all defined functions and some other stuff.
Calling locals()["draw_a"]
returns the funtion draw_a
as variable, which you then execute using ()
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.