auto save

demo3.py

+import time
+
+start_time = time.time()  #开始时间 
+
+list1 = []
+for a in range(0, 1000):
+    for b in range(0, 1000):
+        list1.insert(-1, 0)
+
+end_time = time.time()  #结束时间
+
+result = end_time - start_time
+print('程序运行时间是',result)
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demo4.py

+alist = [20, 17, 9, 13, 5, 6]
+
+for i in range(len(alist)-1): #i 比较几轮
+    for j in range(len(alist)-1-i):   # j  =  0 1 2 3 4 5        j索引
+        if alist[j]>alist[j+1]:
+            alist[j],alist[j+1] = alist[j+1],alist[j]
+            print(alist)
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