python loop function

for loop in python

1. <span class="com">#for loop format (similar foreach in Java): for identifier in list name:</span>

2. ##>>><span class="pun"></span> movies <span class="pln"></span>=<span class="pun"></span> <span class="pln"></span>[<span class="pun"></span>"movie1"<span class="str"></span>,<span class="pun"></span>"movie2"<span class="str"></span>,<span class="pun"></span>"movie3"<span class="str"></span>]<span class="pun"></span>

3. #>>><span class="pun"> </span><span class="pln">for</span><span class="kwd"> item </span><span class="pln">in</span><span class="kwd"> movies </span><span class="pln">:</span><span class="pun"></span>

4. ##print<span class="pln"></span>(<span class="kwd"></span>item<span class="pun"></span>)<span class="pln"></span><span class="pun"> </span>

6. <span class="pln"></span>

#movie1

7. <span class="pln"></span>

   ##movie2

8. <span class="pln"></span>

   movie3

9. <span class="pln"></span>The for loop in Python is similar to the foreach loop in Java. See the comments for the fixed format

   Among them: for means the beginning of the loop and should appear in front of the identifier; in separates the list to be looped from the identifier; : is placed after the list name to indicate the start of the list processing code; please note that the list processing code must be placed Below the for loop and indented! ! !

   When the for loop starts, Python will assign each value in the list to the identifier, which also means that the value of the identifier is different each time the loop is executed; the loop will continue to iterate until the processing is completed All data in the list.

   while loop in python
   

   1. <span class="com">while loop format: while loop condition: </span>

   2. #>>> <span class="pln"></span>while count <span class="pln"> </span>< len<span class="pln"></span>(movies<span class="pln"></span>) <span class="pln"></span>:

   3. <span class="pln">##print</span><span class="kwd">(</span><span class="pun">movies</span><span class="pln">[</span><span class="pun">count</span><span class="pln">])</span><span class="pun"></span>

   4. ## count

      =<span class="pln"></span> count <span class="pln"></span> 1<span class="pln"></span>

   6. <span class="pln"></span>

   movie1

   7. <span class="pln"> </span>

   movie2

   8. </li><li><p><code class="py" style="line-height: 1.8; margin: 1px 5px; vertical-align: middle; display: inline-block; font-family: "Courier New", sans-serif !important; font-size: 12px !important; background-color: rgb(245, 245, 245) !important; border: 1px solid rgb(204, 204, 204) !important; padding: 0px 5px !important; border-radius: 3px !important;"><span class="pln">movie3</span>

   Compared with the for loop, the while loop has more conditional judgment statements, both You can customize the conditions for the end of the loop

   Python's judgment
   

   1. if<span class="pln"> </span>Satisfy a certain condition<span class="pln"> </span>:

   2. <span class="pln"></span>##Execute certain statements

   3. ##else<span class="kwd"> </span><span class="pln">:</span><span class="pun"></span>

   4. <span class="pln">Execute certain statements</span><span class="pun"></span>

   Note: if Statements and else statements must be added with: at the end, and the code to be executed after if and else must be indented
   Python's function

   1. >>><span class="pun"> new_movies </span><span class="pln">=</span><span class="pun"> </span><span class="pln">[</span><span class="pun">"movie1"</span><span class="str">,</span><span class="pun">"movie2"</span><span class="str">,</span><span class="pun">"movie3"</span><span class="str">,[</span><span class="pun">"movie4_1"</span><span class="str">,</span><span class="pun">"movie4_2"</span><span class="str">,[</span><span class="pun">"movie_4_3_1"</span><span class="str">,</span><span class="pun">"movie_4_3_2"</span> <span class="str">]],</span><span class="pun">"movie5"</span><span class="str">]</span><span class="pun"></span>

   2. ##>> >

      def<span class="pln"></span> listItems(<span class="pln"></span>items)<span class="pln"></span> :<span class="pln"></span>

   3. <span class="pln">        </span><span class="kwd">for</span><span class="pln"> item </span><span class="kwd">in</span><span class="pln"> items </span><span class="pun">:</span>

   4.            if isinstance(item,list)<span class="pln"> </span>:

   5. <span class="pln">                listItems</span><span class="pun">(</span><span class="pln">item</span><span class="pun">)</span>

   6.            else<span class="pln"> </span>:

   7. <span class="pln">                </span><span class="kwd">print</span><span class="pun">(</span><span class="pln">item</span><span class="pun">)</span>

   9. <span class="pln"></span>

   10. <span class="pun">>>></span><span class="pln"> listItems</span><span class="pun">(</span><span class="pln">new_movies</span><span class="pun">)</span>

   11. <span class="pln">movie1</span>

   12. <span class="pln">movie2</span>

   13. ##movie3<span class="pln"></span>

   14. movie4_1<span class="pln"></span>

   15. ##movie4_2<span class="pln"></span>

   16. movie_4_3_1<span class="pln"></span>

   17. ##movie_4_3_2

       <span class="pln"> </span>

   18. movie5

       <span class="pln"></span>

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