在 IDL 中相当于 python 的循环命令

Question

关于将 IDL 中的循环命令转换为 python 的简单问题。

我在 IDL 语法中有以下循环结构：

for ... do begin
   for ... do begin
      if ...
         ...
      endif else begin
         ....
      endelse
   endfor
endfor

现在，我想说的是大致翻译成

for ... :
   for ... :
      if ...
         ...
      end if else:
         ....
      endelse
   endfor
endfor

在python.

但是，我会说 endelse 和 endfor 命令是多余的？但是我应该用什么来代替它们呢？

Answer 1

python 中没有 endif 或 endfor。您取消缩进以表明 elif 是 "else if"

for ... :
   for ... :
      if ...:
         ...
      elif...:

我可能将 "end if begin" 误解为一个新的 if 语句，而不是简单的 else。在那种情况下，它是

 for ... :
   for ... :
      if ...:
         ...
      else:
         ...

Answer 2

你说对了一部分，你只需要放弃 endelse 和 endfor 并将 else if 替换为 elif。

for ... :
   for ... :
      if ...:
         ....
      elif:
         ....

来自 Python documentation，这是一个 If statement 的示例：

>>> x = int(raw_input("Please enter an integer: "))
Please enter an integer: 42
>>> if x < 0:
...     x = 0
...     print 'Negative changed to zero'
... elif x == 0:
...     print 'Zero'
... elif x == 1:
...     print 'Single'
... else:
...     print 'More'
...
More

For statement

>>> # Measure some strings:
... words = ['cat', 'window', 'defenestrate']
>>> for w in words:
...     print w, len(w)
...
cat 3
window 6
defenestrate 12

Answer 3

Python 分组仅依赖于缩进，因此您的 if 和 for 循环/分组不需要 end。

这是有效的Python代码：

for i in range(5):
    print(i)

Answer 4

However, I would say the endelse and endfor commands are redundant? But what should I replace them with?

你不用任何东西代替它们。

来自the Python tutorial：

The body of the loop is indented: indentation is Python’s way of grouping statements. At the interactive prompt, you have to type a tab or space(s) for each indented line. In practice you will prepare more complicated input for Python with a text editor; all decent text editors have an auto-indent facility. When a compound statement is entered interactively, it must be followed by a blank line to indicate completion (since the parser cannot guess when you have typed the last line). Note that each line within a basic block must be indented by the same amount.

要结束一个块，只需return到上一级缩进即可。

在 IDL 中相当于 python 的循环命令

Loop commands equivalent in IDL to python

python

idl-programming-language