Python编程从入门到实践-2变量上

2.2 变量

message = "Hello Python world!"
print (message)

message = "Hello Pyhton Crash Course world!"
print (message)

Hello Python world!
Hello Pyhton Crash Course world!

2.2.2 使用变量时避免命名错误

message = "Hello Python Crash Course reader!"
print (mesage)

print (mesage)
NameError: name 'mesage' is not defined

2.3 字符串

print ("This is a string.")
print ('This is also a string.')

This is a string.
This is also a string.

2.3.1 使用方法修改字符串的大小写

name = "ada lovalace"
print (name.title())

Ada Lovalace

name = "ada Lovalace"
print (name.upper())

ADA LOVALACE

name = "ada Lovalace"
print (name.lower())

ada lovalace

2.3.2 合并(拼接)字符串

first_name = "ada"
last_name = "lovelace"
full_name = first_name + " " + last_name

print (full_name)

ada lovelace

first_name = "ada"
last_name = "lovelace"
full_name = first_name + " " + last_name

print ("Hello, " + full_name.title() + "!")

Hello, Ada Lovelace!

first_name = "ada"
last_name = "lovelace"
full_name = first_name + " " + last_name

message = "Hello, " + full_name.title() + "!"
print (message)

Hello, Ada Lovelace!

2.3.3 使用制表符或换行符来添加空白

print ("	Python")
print ("Python")

　　　　Python
Python

print ("Language:
Python
C
JavaScript")

Language:
Python
C
JavaScript

print ("Languages:
	Python
	C
	JaveScript")

Languages:
　　　　Python
　　　　C
　　　　JaveScript