Python print函式用法，print 格式化輸出

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使用print輸出各型的

字串
整數
浮點數
出度及精度控制
strHello = ‘Hello Python’
print strHello

#輸出結果：Hello Python
#直接出字串

1.格式化輸出整數
python print也支援引數格式化，與C言的printf似，

strHello = “the length of (%s) is %d” %(‘Hello World’,len(‘Hello World’))
print strHello

#輸出果：the length of (Hello World) is 11

2.格式化輸出16制整數
nHex = 0x20

#%x --- hex 十六進位制
#%d --- dec 十進位制
#%d --- oct 八進位制
 

print “nHex = %x,nDec = %d,nOct = %o” %(nHex,nHex,nHex)

#輸出結果：nHex = 20,nDec = 32,nOct = 40
#使用整數的各個制列印同一個數

3.格式化輸出浮點數(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
#前面填充字元
print "PI = %06d" % int(math.pi)

#輸出結果
#PI = 3.141593
#PI =      3.142
#PI = 3.142
#PI = 000003
#浮點數的格式化，精度、度和

4.格式化輸出字串(string)
#precise = 3
print "%.3s " % ("jcodeer")
#precise = 4
print "%.*s" % (4,"jcodeer")
#width = 10,precise = 3
print "%10.3s" % ("jcodeer")
#輸出結果：
#jco
#jcod
#       jco
#同於字串也存在精度、度和。
5.輸出列表(list)
l = [1,2,3,4,'jcodeer']
print l
#輸出結果：[1, 2, 3, 4, 'jcodeer']
#於list直接列印即可
'''6.出字典(dictionary)'''
d = {1:'A',2:'B',3:'C',4:'D'}
print d
#輸出結果：{1: 'A', 2: 'B', 3: 'C', 4: 'D'}
#同python也是支援dictionary出的

6.python print自動換行
print 會自動在行末加上回車,如果不需回車，只需在print語句的結尾新增一個逗號”,“，就可以改變它的行為。

for i in range(0,5):
print i,
或直接使用下面的函式進行輸出：

sys.stdout.write(“輸出的字串”)
7. 萬能的 %r
將後面給的引數原樣列印出來，帶有型別資訊。

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 didn’t sing.”,
“So I said goodnight.”
)
輸出結果：

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 didn’t sing.” ‘So I said goodnight.’

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