python - 删除 python 3 中的尾随空格

Question

我制作的程序有点问题。我正在让它显示钻石，但我遇到了问题，这是我的代码:

a = input("Enter width: ")
a = int(a)
b = a
for i in range(a):
  i = i + 1
  b = a - i
  text = " " * b + " " + "* " * i
  print(text[:-1])
for i in range(a):
  i = i + 1
  b = a - i
  text = " " * i + " " + "* " * b
  print(text[:-1])

感谢大家的帮助!这就是答案

Answer 1

那是因为print不返回字符串，它返回None。

>>> print(print("foo"))
foo
None

也许您想这样做:

text = " " * i + " " + "* " * b
print (text[:-1])

要更好地删除尾随空格，请使用 str.rstrip:

>>> "foo ".rstrip()
'foo'

关于 str.rstrip 的帮助:

>>> print (str.rstrip.__doc__)
S.rstrip([chars]) -> str

Return a copy of the string S with trailing whitespace removed.
If chars is given and not None, remove characters in chars instead.