python learning if,for,break and all

Author: Hecp

learning/helloWorld.py

@@ -1,4 +1,55 @@
+# Hello World
 print("Hello World!");
 
+print("variable...")
+# variable
 name = input("please enter your name: ");
-print("Hello,",name,"!");
+print("Hello,",name,"!");
+
+print("if statements...")
+# if statements
+x = int(input("Please enter an integer: "))
+if x < 0:
+	x = 0
+	print("Negative changed to zero!")
+elif x == 0:
+	print("Zero")
+elif x == 1:
+	print("Single")
+else:
+	print("More")
+
+print("for statements...")
+# for statements
+a = ["cat", "dog", "pig"]
+for x in a:
+	print(x, len(x))
+
+print("break and 循环中的else...")
+# break and 循环中的else
+# 循环可以有一个 else 子句；它在循环迭代完整个列表（对于 for ）或执行条件为 false （对于 while ）时执行，
+# 但循环被 break 中止的情况下不会执行。
+for n in range(2, 10):
+	for x in range(2, n):
+		if n % x == 0:
+			print(n, "equal", x, "*", n//x)
+			break
+	# 这个else语句对应的第二个for循环（不是最近的if语句），它会在第二个for循环执行完时执行，
+	# 但循环被break中止的情况下不会执行。		
+	else:
+			print(n, "is a prime number")
+			
+print("continue...")
+# continue
+for num in range(2, 10):
+	if num % 2 == 0:
+		print("Found an even number", num)
+		continue
+	print("Found a number", num)
+	
+print("pass statements...")
+print("pass 语句什么也不做。它用于那些语法上必须要有什么语句，但程序什么也不做的场合，",
+"另一方面， pass 可以在创建新代码时用来做函数或控制体的占位符。")
+# pass statements
+while True:
+	pass