1 函数input()的工作原理
1.1 函数input() 让程序暂停运行,等待用户输入一些文本。获取用户输入后,python将其存储在一个变量中,以方便你使用。使用input函数,python会将用户输入解读为字符串。
example 1
1.2 在提示末尾包含一个空格,可将提示与用户输入分开,让用户清楚地知道其输入始于何处。
example 2
python
prompt
=
"If you tell us who you are,we can personalize the messages you see."
prompt
+=
"\nWhat is your first name?"
name
=
input
(
prompt
)
print("\nHello,"+name+"!")
1.3 使用int()来获取数值输入
可以使用int函数对用户输入的数值,从字符串的形式转变为数值。
example 3
1.4 使用%函数将两个数相除并返回余数
example 4
2.1 与for循环的区别
for 循环用于针对集合中的每个元素的一个代码块,而while循环不断地进行,直到指定的条件不满足。
while 循环的规则
example 5
python
prompt
=
"\nTell me something,and I will repeat it back to you:"
prompt
+=
"\nEnter 'quit' to end the program."
message
=
""
while
message
!=
'quit'
:
message
=
input
(
prompt
)
if
message
!=
'quit'
:
print
(
message
)
2.2 使用标志
可定义一个变量,用于判断整个程序是否处于活动状态。
example 6
python
prompt
=
"\nTell me something,and I will repeat it back to you:"
prompt
+=
"\nEnter 'quit' to end the program."
active
=
True
while
active
:
message
=
input
(
prompt
)
if
message
==
'quit'
:
active
=
False
else
:
print
(
message
)
2.3 使用break退出循环
break语句用于控制程序流程,可使用它来控制哪些代码将执行,哪些代码不执行。
2.4 使用continue
continue作用:使用continue,根据条件测试结果决定是否继续执行循环,返回到循环开头。
example 7
2.5 避免无限循环
Tips:如果程序陷入无限循环,可按Ctrl+C,停止循环。
3.1 在列表之间移动元素
example 8
python
#首先,创建一个待验证用户列表
#和一个用于存储以验证用户的空列表
unconfirmed_users
=
[
'alice'
,
'brian'
,
'candace'
]
confirmed_users
=
[
]
#验证每一个用户,直到没有未验证用户为止
#将每个经过验证的列表都移到已验证用户列表中
while
unconfirmed_users
:
current_user
=
unconfirmed_users
.
pop
(
)
print
(
"Verifying user:"
+
current_user
.
title
(
)
)
confirmed_users
.
append
(
current_user
)
#显示所有已经验证的用户
print
(
"\nThe following users have been confirmed:"
)
for
confirmed_user
in
confirmed_users
:
print
(
confirmed_users
.
title
(
)
)
3.2 删除包含特定值的所有列表元素
python
pets
=
[
'dog'
,
'cat'
,
'dog'
,
'goldfish'
,
'cat'
,
'rabbit'
,
'cat'
]
print
(
pets
)
while
'cat'
in
pets
:
pets
.
remove
(
'cat'
)
print
(
pets
)
3.3 使用用户输入来填充字典
example 9
python
responses
=
{
}
#设置一个标志,指出调查是否继续
polling_active
=
True
while
polling_active
:
#提示输入被调查者的名字和回答
name
=
input
(
"\nWhat is your name?"
)
response
=
input
(
"Which mountain would you like to climb someday?"
)
#将答卷存储在字典中
responses
[
name
]
=
response
#看看是否还有人要参与调查
repeat
=
input
(
"Would you like to let another person respond?(yes/no)"
)
if
repeat
==
'no'
:
polling_active
=
False
#调查结果,显示结果
print
(
"\n----Poll Results----"
)
for
name
,
response
in
responses
.
items
(
)
:
print
(
name
+
" Would like to climb "
+
response
+
"."
)
运行结果如下:
python
What
is
your name?Jerry
Which mountain would you like to climb someday?lu
Would you like to let another person respond?
(
yes
/
no
)
yes
What
is
your name?Tom
Which mountain would you like to climb someday?tai
Would you like to let another person respond?
(
yes
/
no
)
no
-
-
-
-
Poll Results
-
-
-
-
Jerry Would like to climb lu
.
Tom Would like to climb tai
.
1 函数input()的工作原理
1.1 函数input() 让程序暂停运行,等待用户输入一些文本。获取用户输入后,python将其存储在一个变量中,以方便你使用。使用input函数,python会将用户输入解读为字符串。
example 1
1.2 在提示末尾包含一个空格,可将提示与用户输入分开,让用户清楚地知道其输入始于何处。
example 2
python
prompt
=
"If you tell us who you are,we can personalize the messages you see."
prompt
+=
"\nWhat is your first name?"
name
=
input
(
prompt
)
print("\nHello,"+name+"!")
1.3 使用int()来获取数值输入
可以使用int函数对用户输入的数值,从字符串的形式转变为数值。
example 3
1.4 使用%函数将两个数相除并返回余数
example 4
2.1 与for循环的区别
for 循环用于针对集合中的每个元素的一个代码块,而while循环不断地进行,直到指定的条件不满足。
while 循环的规则
example 5
python
prompt
=
"\nTell me something,and I will repeat it back to you:"
prompt
+=
"\nEnter 'quit' to end the program."
message
=
""
while
message
!=
'quit'
:
message
=
input
(
prompt
)
if
message
!=
'quit'
:
print
(
message
)
2.2 使用标志
可定义一个变量,用于判断整个程序是否处于活动状态。
example 6
python
prompt
=
"\nTell me something,and I will repeat it back to you:"
prompt
+=
"\nEnter 'quit' to end the program."
active
=
True
while
active
:
message
=
input
(
prompt
)
if
message
==
'quit'
:
active
=
False
else
:
print
(
message
)
2.3 使用break退出循环
break语句用于控制程序流程,可使用它来控制哪些代码将执行,哪些代码不执行。
2.4 使用continue
continue作用:使用continue,根据条件测试结果决定是否继续执行循环,返回到循环开头。
example 7
2.5 避免无限循环
Tips:如果程序陷入无限循环,可按Ctrl+C,停止循环。
3.1 在列表之间移动元素
example 8
python
#首先,创建一个待验证用户列表
#和一个用于存储以验证用户的空列表
unconfirmed_users
=
[
'alice'
,
'brian'
,
'candace'
]
confirmed_users
=
[
]
#验证每一个用户,直到没有未验证用户为止
#将每个经过验证的列表都移到已验证用户列表中
while
unconfirmed_users
:
current_user
=
unconfirmed_users
.
pop
(
)
print
(
"Verifying user:"
+
current_user
.
title
(
)
)
confirmed_users
.
append
(
current_user
)
#显示所有已经验证的用户
print
(
"\nThe following users have been confirmed:"
)
for
confirmed_user
in
confirmed_users
:
print
(
confirmed_users
.
title
(
)
)
3.2 删除包含特定值的所有列表元素
python
pets
=
[
'dog'
,
'cat'
,
'dog'
,
'goldfish'
,
'cat'
,
'rabbit'
,
'cat'
]
print
(
pets
)
while
'cat'
in
pets
:
pets
.
remove
(
'cat'
)
print
(
pets
)
3.3 使用用户输入来填充字典
example 9
python
responses
=
{
}
#设置一个标志,指出调查是否继续
polling_active
=
True
while
polling_active
:
#提示输入被调查者的名字和回答
name
=
input
(
"\nWhat is your name?"
)
response
=
input
(
"Which mountain would you like to climb someday?"
)
#将答卷存储在字典中
responses
[
name
]
=
response
#看看是否还有人要参与调查
repeat
=
input
(
"Would you like to let another person respond?(yes/no)"
)
if
repeat
==
'no'
:
polling_active
=
False
#调查结果,显示结果
print
(
"\n----Poll Results----"
)
for
name
,
response
in
responses
.
items
(
)
:
print
(
name
+
" Would like to climb "
+
response
+
"."
)
运行结果如下:
python
What
is
your name?Jerry
Which mountain would you like to climb someday?lu
Would you like to let another person respond?
(
yes
/
no
)
yes
What
is
your name?Tom
Which mountain would you like to climb someday?tai
Would you like to let another person respond?
(
yes
/
no
)
no
-
-
-
-
Poll Results
-
-
-
-
Jerry Would like to climb lu
.
Tom Would like to climb tai
.