关于后端:Python入门系列五一篇搞懂python语句

If语句

elif关键字是pythons示意“如果后面的条件不为真，那么试试这个条件”。

The else keyword catches anything which isn't caught by the preceding conditions.

a = 200b = 33if b > a:  print("b is greater than a")elif a == b:  print("a and b are equal")else:  print("a is greater than b")

如果只有一条语句要执行，则能够将其与If语句放在同一行。

if a > b: print("a is greater than b")

如果只有一条语句要执行，一条用于If，另一条用于else，则能够将所有语句放在同一行中

a = 2b = 330print("A") if a > b else print("B")

and关键字是一个逻辑运算符，用于组合条件语句

a = 200b = 33c = 500if a > b and c > a:  print("Both conditions are True")

or关键字是一个逻辑运算符，用于组合条件语句

a = 200b = 33c = 500if a > b or a > c:  print("At least one of the conditions is True")

应用while循环，只有条件为true，咱们就能够执行一组语句。

i = 1while i < 6:  print(i)  i += 1

应用break语句，即便while条件为true，咱们也能够进行循环

i = 1while i < 6:  print(i)  if i == 3:    break  i += 1

应用continue语句，咱们能够进行以后迭代，而后持续下一个迭代

i = 0while i < 6:  i += 1  if i == 3:    continue  print(i)

应用else语句，当条件不再为真时，咱们能够运行一段代码

i = 1while i < 6:  print(i)  i += 1else:  print("i is no longer less than 6")

fruits = ["apple", "banana", "cherry"]for x in fruits:  print(x)

for循环中的else关键字指定循环实现时要执行的代码块

for x in range(6):  print(x)else:  print("Finally finished!")

for x in range(6):  if x == 3: break  print(x)else:  print("Finally finished!")#If the loop breaks, the else block is not executed.

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