Python print function usage, print format output

Original address: http://blog.csdn.net/zanfeng/article/details/52164124

Use print to output various types of

String
Integer
Floating point
Output and precision control
strHello = ‘Hello Python’
print strHello
#Output: Hello Python
#Directly out of the string


1. Format the output integer
Python print also supports parameter formatting, similar to C's printf,

strHello = "the length of (% s) is% d"% (‘Hello World’, len (‘Hello World’))
print strHello
#Output fruit: the length of (Hello World) is 11


2. Format the 16-bit integer
nHex = 0x20
#% x --- hex hex
#% d --- dec decimal
#% d --- oct octal
 
print "nHex =% x, nDec =% d, nOct =% o"% (nHex, nHex, nHex)
 
#Output results: nHex = 20, nDec = 32, nOct = 40
#Print the same number using the integer system


If you need to output binary, you can use the python function 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. Format the output floating point number (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
#Front Fill Character
print "PI =% 06d"% int (math.pi)
 
#Output result
#PI = 3.141593
#PI = 3.142
#PI = 3.142
#PI = 000003
#Floating point formatting, precision, degree and


4. Format the output string (string)
#precise = 3
print "% .3s"% ("jcodeer")
#precise = 4
print "%. * s"% (4, "jcodeer")
#width = 10, precise = 3
print "% 10.3s"% ("jcodeer")
#Output results:
#jco
#jcod
# jco
#Same as string, there are precision, degree sum.


5. Output list
l = [1,2,3,4, ‘jcodeer’]
print l
#Output result: [1, 2, 3, 4, ‘jcodeer’]
#Print directly on the list
‘‘ ‘6. dictionary (‘ dictionary ’‘ ‘
d = {1: ‘A’, 2: ‘B’, 3: ‘C’, 4: ‘D’
print d
#Output result: {1: ‘A’, 2: ‘B’, 3: ‘C’, 4: ‘D’}
#Same as python also supports dictionary


6.python print wrap
print will automatically add a carriage return at the end of the line. If you don't need a carriage return, just add a comma "," at the end of the print statement to change its behavior.

for i in range (0,5):
    print i,


Or use the following function directly for output:

sys.stdout.write ("Output string")


7. Almighty% r
A colleague asked me what is the purpose of print "% r" in python and was asked.

I have used python for so many years and have never used print% r.

Checked online and found that% r is a universal format payment, it will print out the parameters given later with the type information.

python print% r case
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 did n’t sing.",
 "So I said goodnight."
 )


Output results:

$ 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 did n’t sing.” ‘So I said goodnight.’
$


Python print function usage, print formatted output