Python—格式化输出

Python提供了很多种格式化方式（包括但不限于以下几种）：

[,]分隔

name = 'jack'
age = -0.5

print(name, 'is', age, 'years old.')

jack is -0.5 years old.

---

[+]号

name = 'jack'
age = -0.5

print(name + ' is ' + str(age) + ' years old.')

jack is -0.5 years old.

---

[%]号

name = 'jack'
age = -0.5

print('%s is %.2f years old.'%(name, age))

jack is -0.50 years old.

---

f 字符串

name = 'jack'
age = -0.5

print(f'name is {name}')
print(f'{name}\'s age is {age}')
print(f'{name.upper()}')
print(f'{name[0]}')

name is jack
jack's age is -0.5
JACK
j

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str.format方法

name = 'jack'
age = -0.5

print('name={}, age={}'.format(name, age))
print('name={1}, age={0}'.format(age, name))
print('name={a}, age={b}'.format(a=name, b=age))

name=jack, age=-0.5
name=jack, age=-0.5
name=jack, age=-0.5

---

format内置函数

name = 'jack'
age = -0.5

print(format(name))
print(format(age, '5f'))

jack
-0.500000

---

Formatter类

from string import Formatter

form = Formatter()
name = 'jack'
age = -0.5

print(form.format('name={}, age={}', name, age))
print(form.format('name={1}, age={0}', age, name))
print(form.format('name={a}, age={b}', b=age, a=name))

name=jack, age=-0.5
name=jack, age=-0.5
name=jack, age=-0.5

---

printf风格

name = 'jack'
age = -0.5

print('%(x)s'%{'x':name})
print('%(x).5f'%{'x':age})

jack
-0.50000

---

Template

from string import Template

name = 'jack'
age = -0.5

s = Template('$a is $b years old').substitute(a=name, b=age)
print(s)

jack is -0.5 years old