cycleuser / duke-sta-663-cn Goto Github PK

x = 5
def f(alist): 
    for i in range(x): 
        alist.append(i) 
    return alist 
alist = [1,2,3] 
ans = f(alist)
print ans 
print alist # alist has been changed!
##输出结果
#[1, 2, 3, 0, 1, 2, 3, 4] 
#[1, 2, 3, 0, 1, 2, 3, 4] 

x = 5
def f(alist=None):
    if alist is None:
        alist = [] 
    alist = alist + [i for i in range(x)] 
    return alist 
alist = [1,2,3] 
ans = f(alist) 
print ans 
print alist 
###输出结果如下###
#[1, 2, 3, 0, 1, 2, 3, 4] 
#[1, 2, 3]