Python中遍历整个列表及注意点（参考书籍Python编程从入门到实践）

1. 利用for循环遍历整个列表

magicians = ['alice', 'dsvid', 'carolina']
# 遍历整个列表
for magician in magicians:
    print(magician)

2. 使得打印结果变得更加有实际意义

for magician in magicians:
    print(magician.title() + ', that was a great trick!')

运行结果：

Alice, that was a great trick!
Dsvid, that was a great trick!
Carolina, that was a great trick!

for代码行后边缩进的代码块都是循环的一部分，继续增加打印语句：

for magician in magicians:
    print(magician.title() + ', that was a great trick!')
    print("I can't wait to see your next trick, " + magician.title() + "\n")

运行结果：

 

3. 对于for循环后边的属于循环模块的代码行一定要缩进。

3.1 若没有缩进：

for magician in magicians:
print(magician.title() + ', that was a great trick!')

运行结果会报错：

IndentationError: expected an indented block

3.2 若有缩进的，有没有缩进的：

for magician in magicians:
    print(magician.title() + ', that was a great trick!')
print("I can't wait to see your next trick, " + magician.title() + "\n")

程序运行不会出错，但是没有缩进的代码将在循环结束之后执行一次，只打印出有关列表最后一个元素的信息：

Alice, that was a great trick!
Dsvid, that was a great trick!
Carolina, that was a great trick!
I can't wait to see your next trick, Carolina

3.3 若缩进了本应在循环结束之后执行的代码，则这些代码将针对每个元素循环执行一次，程序不会报错。

 

4. 对于for循环还要注意的一点是——for语句的末尾千万不要忘了冒号（太容易忘了，太容易忘了，太容易忘了。。。）。

一旦忘记冒号，程序运行就会报错：

SyntaxError: invalid syntax