Python: slicing

 

# python slicing 和函数range 差不多， 起始值，最后值，步长值
a='abcdefghijklmnopqrstuvwxyz'
print(a[:],end=' \n') # abcdefghijklmnopqrstuvwxyz
print(a[:5], end=' \n') #abcde
print(a[:-1], end=' \n') #abcdefghijklmnopqrstuvwxy
print(a[4:], end=' \n') #efghijklmnopqrstuvwxyz
print(a[-3:], end=' \n') #xyz
print(a[2:-1], end=' \n') #cdefghijklmnopqrstuvwxy
print(a[-3:-1], end=' \n') #xy
print(a[12:6:-1], end=' \n') #mlkjih
print(a[::-1], end=' \n') #zyxwvutsrqponmlkjihgfedcba
print()
a=['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z']
print(a[:],end=' \n') # abcdefghijklmnopqrstuvwxyz
print(a[:5], end=' \n') #abcde
print(a[:-1], end=' \n') #abcdefghijklmnopqrstuvwxy
print(a[4:], end=' \n') #efghijklmnopqrstuvwxyz
print(a[-3:], end=' \n') #xyz
print(a[2:-1], end=' \n') #cdefghijklmnopqrstuvwxy
print(a[-3:-1], end=' \n') #xy
print(a[12:6:-1], end=' \n') #mlkjih
print(a[::-1], end=' \n') #zyxwvutsrqponmlkjihgfedcba