Table of contents
4. Python conversion specifiers
Python print string has the following implementation methods, one based on %s, one using format, and the f function can also be used.
1. %s
This is the easiest way, but you need to pay attention to the order.
string = "Hello %s %s"%("world",'!')
print(string)
# Hello world !2. format
There are two ways to pass parameters to format, one is in order and the other is in dictionary.
string = 'Hello {0} {1}'.format("World","!")
print (string)
# Hello World !
string = "Hello {name} {placeholder}".format(name='World',placeholder='!')
print (string)
# Hello World !
# 传递参数的方式
## list
parameters=["World","!"]
string = 'Hello {0} {1}'.format(*parameters)
print(string)
# Hello World !
## dict
parameters=dict(name='World',placeholder='!')
string = "Hello {name} {placeholder}".format(name='World',placeholder='!')
print(string)
# Hello World !3. f
f is a relatively new function that can support calculations in strings and print out.
a = 1
b = 2
string = f"a={a},b={b},a+b={a+b}"
print(string)
# a=1,b=2,a+b=3
string = f"a={a},b={b},a+b={a+b:.2f}"
print(string)
# a=1,b=2,a+b=3.00
4. Python conversion specifiers
| conversion specifier | explain |
|---|---|
| %d、%i | Convert to signed decimal integer |
| %o | Convert to signed octal integer |
| %x、%X | Convert to signed hexadecimal integer |
| %e | Convert to a floating point number expressed in scientific notation (e lowercase) |
| %E | Convert to a floating point number represented by scientific notation (uppercase E) |
| %f、%F | Convert to decimal floating point |
| %g | Smart select to use %f or %e format |
| %G | Smart select to use %F or %E format |
| %c | Formatting characters and their ASCII codes |
| %r | Use the repr() function to convert an expression to a string |
| %s | Use the str() function to convert an expression to a string |
5. Formatted output numbers
# 保留两位小数
number = "number: %.2f" % (0.23423)
# number = "number: {0:.2f}".format(0.23423)
# number = "number: {num:.2f}".format(num=0.23423)
print (number)
# number: 0.23
# 转换成百分数
number = "number: %.2f%%" % (0.23423*100)
# number = "number: {0:.2f}%".format(0.23423*100)
# number = "number: {num:.2f}%".format(num=0.23423*100)
print(number)
# number: 23.42%6. Add color
from termcolor import colored
string = "red string"
print(colored(string,'red'))
# red string