python学习[第二篇] 基础二

# only if block

if condition:
    if_true_block

# if_else  block

if condition:
    if_true_block
else:
    if_false_block

# if_elif_else block 
if condition:
    if_true_block
elif condition: 
    elif_true_block
elif condition: 
    elif_true_block
else:
    all_false_block
# if 嵌套 block
if outer_condition:
    if inner_condition:
        inner_condition_true_block
    else:
        inner_condition_false_block
else:
      outer_if_false_block

# while only
while condition :
     while_clause

# while-else clause:

while condition:
     while_clause
else:
     else_cluase

# for结构

for  iter_var in iterable:
    suite_to_repeat