使用 print 输出各型的
字符串
整数
浮点数
出度及精度控制
- strHello = Hello Python
- print strHello
- # 输出结果: Hello Python
- # 直接出字符串
1. 格式化输出整数
python print 也支持参数格式化, 与 C 言的 printf 似,
- strHello = "the length of (%s) is %d" %(Hello World,len(Hello World))
- print strHello
- # 输出果: the length of (Hello World) is 11
2. 格式化输出 16 制整数
- nHex = 0x20
- #%x --- hex 十六进制
- #%d --- dec 十进制
- #%d --- oct 八进制
- print "nHex = %x,nDec = %d,nOct = %o" %(nHex,nHex,nHex)
- # 输出结果: nHex = 20,nDec = 32,nOct = 40
- # 使用整数的各个制打印同一个数
如果需要输出二进制的话, 可以使用 python 函数 bin()
- Python 2.7.6 (default, Nov 10 2013, 19:24:18) [MSC v.1500 32 bit (Intel)] on win
- 32
- Type "help", "copyright", "credits" or "license" for more information.
- >>> bin(789)
- 0b1100010101
- >>>
3. 格式化输出浮点数 (float)
- import math
- #default
- print "PI = %f" % math.pi
- #width = 10,precise = 3,align = left
- print "PI = %10.3f" % math.pi
- #width = 10,precise = 3,align = rigth
- print "PI = %-10.3f" % math.pi
- # 前面填充字符
- print "PI = %06d" % int(math.pi)
- # 输出结果
- #PI = 3.141593
- #PI = 3.142
- #PI = 3.142
- #PI = 000003
- # 浮点数的格式化, 精度度和
4. 格式化输出字符串 (string)
- #precise = 3
- print "%.3s" % ("jcodeer")
- #precise = 4
- print "%.*s" % (4,"jcodeer")
- #width = 10,precise = 3
- print "%10.3s" % ("jcodeer")
- # 输出结果:
- #jco
- #jcod
- # jco
- # 同于字符串也存在精度度和
5. 输出列表 (list)
- l = [1,2,3,4,jcodeer]
- print l
- # 输出结果:[1, 2, 3, 4, jcodeer]
- # 于 list 直接打印即可
6. 出字典 (dictionary)
- d = {1:A,2:B,3:C,4:D}
- print d
- # 输出结果:{1: A, 2: B, 3: C, 4: D}
- # 同 python 也是支持 dictionary 出的
6.python print 自动换行
print 会自动在行末加上回车, 如果不需回车, 只需在 print 语句的结尾添加一个逗号,, 就可以改变它的行为
for i in range(0, 5) : print i,
或直接使用下面的函数进行输出:
sys.stdout.write("输出的字串")
7. 万能的 %r
有个同事问我 python 里面 print %r 是什么用途, 被问倒了
用了这么些年的 python, 还没用过 print %r
网上查了一下, 发现 %r 是一个万能的格式付, 它会将后面给的参数原样打印出来, 带有类型信息
python print %r 案例
- formatter = "%r %r %r %r"
- print formatter % (1, 2, 3, 4)
- print formatter % ("one", "two", "three", "four")
- print formatter % (True, False, False, True)
- print formatter % (formatter, formatter, formatter, formatter)
- print formatter % (
- "I had this thing.",
- "That you could type up right.",
- "But it didnt sing.",
- "So I said goodnight."
- )
输出结果:
- $ python ex8.py
- 1 2 3 4
- one two three four
- True False False True
- %r %r %r %r %r %r %r %r %r %r %r %r %r %r %r %r
- I had this thing. That you could type up right. "But it didnt sing." So I said goodnight.
- $
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