湛江网站关键词优化关键词筛选

1. print()

传递给函数的值称为参数。

引号没有打印在屏幕上，它们只是表示字符串的起止，不是字符串的一部分。可以用这个函数在屏幕上打印出空行，只要调用 print() 就可以了，括号内没有任何东西。

Microsoft Windows [版本 6.1.7601]
版权所有 (c) 2009 Microsoft Corporation。保留所有权利。C:\Users\foreverstrong>python
Python 3.6.0 (v3.6.0:41df79263a11, Dec 23 2016, 08:06:12) [MSC v.1900 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> print("Hello World!")
Hello World!
>>> exit()C:\Users\foreverstrong>

Microsoft Windows [版本 6.1.7601]
版权所有 (c) 2009 Microsoft Corporation。保留所有权利。C:\Users\foreverstrong>python
Python 3.6.0 (v3.6.0:41df79263a11, Dec 23 2016, 08:06:12) [MSC v.1900 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> width = 5
>>> width
5
>>> symbol1 = '*'
>>> symbol1
'*'
>>> print(symbol1 * width)
*****
>>> symbol2 = 'x'
>>> symbol2
'x'
>>> print(symbol2 * width)
xxxxx
>>> symbol3 = '0'
>>> symbol3
'0'
>>> print(symbol3 + (' ' * (width - 2)) + symbol3)
0   0
>>> print(symbol2 + (' ' * (width + 2)) + symbol2)
x       x
>>> print(symbol1 + (' ' * (width + 0)) + symbol1)
*     *
>>> exit()C:\Users\foreverstrong>

2. 浮点数 (float)

#!/usr/bin/env python3
# -*- coding:utf-8 -*-import math# default
print("PI = %f" % math.pi)# width = 10, precision = 3, alignment = right
print("PI = %10.3f" % math.pi)# width = 10, precision = 3, alignment = left
print("PI = %-10.3f" % math.pi)# precision = 4
print("PI = %.4f" % math.pi)# precision = 5
print("PI = %.5f" % math.pi)# width = 8
print("PI = %08d" % int(math.pi))

/usr/bin/python3.5 /home/strong/pyqt5_workspace/task_master.py
PI = 3.141593
PI =      3.142
PI = 3.142     
PI = 3.1416
PI = 3.14159
PI = 00000003Process finished with exit code 0

References

[1] Yongqiang Cheng, https://yongqiang.blog.csdn.net/