【三】Python List列表，及切片

H='abcdefghijklmnopqrstuvwxyz'

n=0
for x in list(H):
n=n+1
if n%2 == 0:
print ",",
else:
print x,
print

n=0
while n<len(H):
if n%2==1:
H = H.replace( H[n:n+1],',')
n=n+1
print H

n=0
for x in list(H):
n=n+1
if n%2 == 0:
print "_",
else:
print x,
print

H='abcdefghijklmnopqrstuvwxyz'

#n=0
#for x in list(H):
# print x,
# n=n+1
# if n%4 == 0:
# print
# if n%4 !=0:
# print
# while x<4-(n%4)
# print *
#H='abcdefghijklmnopqrstuvwxyz'
#n=0
#while n<26: