Python 学习入门（8）—— 格式化输出

#!/usr/bin/env python
# it-homer in 2013

import sys
reload(sys)
sys.setdefaultencoding("utf-8")

# %s 格式化为字符串
from math import pi
def test_format():
  str = "hello %s, http://blog.%s.net"   val = ("it-homer", "ithomer")
  print str % val               # hello it-homer, http://blog.ithomer.net 
  print("%s %s %s" % (1, 2.3, ['one', 'two', 'three']))         # 1 2.3 ['one', 'two', 'three']

  print("PI: %.10f" % pi)       # PI: 3.1415926536

  # -：左对齐; +：在转换值之前加上正负号; 
  # “ ”：正数之前保留空格; 0：转换值若位数不够用0填充
  print("PI: %010.2f" % pi)     # PI: 0000003.14
  print("PI: %010.6f" % pi)     # PI: 003.141593

  print("PI: %-10.2f" % pi)     # PI: 3.14
  print("PI: %-10.6f" % pi)     # PI: 3.141593

  print("PI: %10.2f" % pi)     # PI:       3.14
  print("PI: %10.6f" % pi)     # PI:   3.141593

  print("PI: %010.2f" % pi)     # PI: 0000003.14
  print("PI: % 10.2f" % pi)     # PI:       3.14
  
  print("PI: %+10.2f" % pi)     # PI:      +3.14
  print("PI: %-+10.2f" % pi)    # PI: +3.14
  print("PI: %+-10.2f" % pi)    # PI: +3.14

# 模板字符串
from string import Template
def test_format2():
  s = Template('$x, hello $x')
  f = s.substitute(x = 'ithomer')
  print(f)              # ithomer, hello ithomer

  
  # 单词字母替换
  s = Template("It's ${x}homer blog")
  f = s.substitute(x='it')
  print(f)              # It's ithomer blog

  # 用$$插入一个$符号
  s = Template("It's $$ blog $x")
  f = s.substitute(x='ithomer')
  print(f)              # It's $ blog ithomer

  s = Template('A $name go to $blog')
  d = {}
  d['name'] = 'sunboy'
  d['blog'] = 'blog.ithomer.net'
  f = s.substitute(d)
  print(f)              # A sunboy go to blog.ithomer.net

def test_format3():
  num = 20

  # 十进制
  print("%d" % num)     # 20
  print("%u" % num)     # 20

  # 八进制
  print("%o" % num)     # 24

  # 十六进制
  print("%x" % num)     # 14
  print("%X" % num)     # 14

  # 浮点数 
  print("%f" % num)     # 20.000000

  # 科学计数法
  print("%e" % num)     # 2.000000e+01
  print("%E" % num)     # 2.000000E+01
  print("%g" % num)     # 20

def test_format4():
  print("'ithomer'")    # 'ithomer'
  print("\'ithomer")    # 'ithomer

  print("\"ithomer\"")  # "ithomer"
  print("\\ithomer\\")  # \ithomer\
  print("/ithomer/")    # /ithomer/

  print("aa\nbb")       # aa next line bb
  print("aa\bbb")       # abb

  print("aa\rbb")       # bb
  print("aa\tbb")       # aa    bb

  print("aa\000bb")     # aabb

if __name__ == "__main__":
  test_format()
  test_format2()
  test_format3()
  test_format4()