python 库 PrettyTabble 使用与错误

参考链接：http://zetcode.com/python/prettytable/

PrettyTable能在python中生成ASCII 表，可以使用他控制表的很多方面，包括文本对齐、表的边框、列的宽度、对数据进行排序、选择在最后的输出中显示制定的行或者列

支持从CSV、HTML、数据库游标中导入数据，能输出数据到ASCII 或者HTML

安装

pip install pTable

使用

　　产生一个表（通过add_row()),不用指定数据类型

from prettytable import PrettyTable
    
x = PrettyTable()#第一步创建对象

x.field_names = ["City name", "Area", "Population", "Annual Rainfall"]#设置表头名称
#通过 add_row()方法创建一个表
x.add_row(["Adelaide", 1295, 1158259, 600.5])
x.add_row(["Brisbane", 5905, 1857594, 1146.4])
x.add_row(["Darwin", 112, 120900, 1714.7])
x.add_row(["Hobart", 1357, 205556, 619.5])
x.add_row(["Sydney", 2058, 4336374, 1214.8])
x.add_row(["Melbourne", 1566, 3806092, 646.9])
x.add_row(["Perth", 5386, 1554769, 869.4])

print(x)

　　

$ ./create_by_row.py 
+-----------+------+------------+-----------------+
| City name | Area | Population | Annual Rainfall |
+-----------+------+------------+-----------------+
|  Adelaide | 1295 |  1158259   |      600.5      |
|  Brisbane | 5905 |  1857594   |      1146.4     |
|   Darwin  | 112  |   120900   |      1714.7     |
|   Hobart  | 1357 |   205556   |      619.5      |
|   Sydney  | 2058 |  4336374   |      1214.8     |
| Melbourne | 1566 |  3806092   |      646.9      |
|   Perth   | 5386 |  1554769   |      869.4      |
+-----------+------+------------+-----------------+

　　产生一个表（通过add_column())#也是先设置表头名称，然后一下添加一列关于相同的属性的不同的值

#!/usr/bin/python3

from prettytable import PrettyTable
    
x = PrettyTable()

column_names = ["City name", "Area", "Population", "Annual Rainfall"]

x.add_column(column_names[0], ["Adelaide", "Brisbane", "Darwin", 
    "Hobart", "Sydney", "Melbourne", "Perth"])
x.add_column(column_names[1], [1295, 5905, 112, 1357, 2058, 1566, 5386 ])  
x.add_column(column_names[2], [1158259, 1857594, 120900, 205556, 4336374, 
    3806092, 1554769])  
x.add_column(column_names[3], [600.5, 1146.4, 1714.7, 619.5, 1214.8, 
    646.9, 869.4])

print(x)

　　删除 行

　　del_row()通过从零开始的索引来删除指定行

#!/usr/bin/python3

from prettytable import PrettyTable
    
x = PrettyTable()

x.field_names = ["City name", "Area", "Population", "Annual Rainfall"]

x.add_row(["Adelaide", 1295, 1158259, 600.5])
x.add_row(["Brisbane", 5905, 1857594, 1146.4])
x.add_row(["Darwin", 112, 120900, 1714.7])
x.add_row(["Hobart", 1357, 205556, 619.5])
x.add_row(["Sydney", 2058, 4336374, 1214.8])
x.add_row(["Melbourne", 1566, 3806092, 646.9])
x.add_row(["Perth", 5386, 1554769, 869.4])

x.del_row(6)
x.del_row(5)
x.del_row(4)
x.del_row(3)

print(x)
#结果：
$ ./delete_rows.py 
+-----------+------+------------+-----------------+
| City name | Area | Population | Annual Rainfall |
+-----------+------+------------+-----------------+
|  Adelaide | 1295 |  1158259   |      600.5      |
|  Brisbane | 5905 |  1857594   |      1146.4     |
|   Darwin  | 112  |   120900   |      1714.7     |
+-----------+------+------------+-----------------+

　　清空数据：

　　clear_rows()清楚所有的行但是会保留当前表的列名称，而clear（）清除所有的包括行和列名

#!/usr/bin/python3

from prettytable import PrettyTable
    
x = PrettyTable()

x.field_names = ["City name", "Area", "Population", "Annual Rainfall"]

x.add_row(["Adelaide", 1295, 1158259, 600.5])
x.add_row(["Brisbane", 5905, 1857594, 1146.4])
x.add_row(["Darwin", 112, 120900, 1714.7])
x.add_row(["Hobart", 1357, 205556, 619.5])
x.add_row(["Sydney", 2058, 4336374, 1214.8])
x.add_row(["Melbourne", 1566, 3806092, 646.9])
x.add_row(["Perth", 5386, 1554769, 869.4])

x.clear_rows()
print(x)
#输出
$ ./clear_rows.py 
+-----------+------+------------+-----------------+
| City name | Area | Population | Annual Rainfall |
+-----------+------+------------+-----------------+
+-----------+------+------------+-----------------+

　　对数据进行排序

　　通过sortby属性，我们可以对指定的列进行排序，reversesort属性控制排序的方向（升序或者降序)

#!/usr/bin/python3

from prettytable import PrettyTable
    
x = PrettyTable()
x.field_names = ["City name", "Area", "Population", "Annual Rainfall"]

x.add_row(["Adelaide", 1295, 1158259, 600.5])
x.add_row(["Brisbane", 5905, 1857594, 1146.4])
x.add_row(["Darwin", 112, 120900, 1714.7])
x.add_row(["Hobart", 1357, 205556, 619.5])
x.add_row(["Sydney", 2058, 4336374, 1214.8])
x.add_row(["Melbourne", 1566, 3806092, 646.9])
x.add_row(["Perth", 5386, 1554769, 869.4])

print("Table sorted by population:")
x.sortby = "Population"
print(x)

print()

print("Table sorted by city in descendig order:")
x.sortby = "City name"
x.reversesort = True
print(x)
#第一次的输出：
$ ./sorting.py 
Table sorted by population:
+-----------+------+------------+-----------------+
| City name | Area | Population | Annual Rainfall |
+-----------+------+------------+-----------------+
|   Darwin  | 112  |   120900   |      1714.7     |
|   Hobart  | 1357 |   205556   |      619.5      |
|  Adelaide | 1295 |  1158259   |      600.5      |
|   Perth   | 5386 |  1554769   |      869.4      |
|  Brisbane | 5905 |  1857594   |      1146.4     |
| Melbourne | 1566 |  3806092   |      646.9      |
|   Sydney  | 2058 |  4336374   |      1214.8     |
+-----------+------+------------+-----------------+
#第二次的输出
Table sorted by city in descendig order:
+-----------+------+------------+-----------------+
| City name | Area | Population | Annual Rainfall |
+-----------+------+------------+-----------------+
|   Sydney  | 2058 |  4336374   |      1214.8     |
|   Perth   | 5386 |  1554769   |      869.4      |
| Melbourne | 1566 |  3806092   |      646.9      |
|   Hobart  | 1357 |   205556   |      619.5      |
|   Darwin  | 112  |   120900   |      1714.7     |
|  Brisbane | 5905 |  1857594   |      1146.4     |
|  Adelaide | 1295 |  1158259   |      600.5      |
+-----------+------+------------+-----------------+

　　对齐数据

　　align属性控制，取值为：l、c、r

#!/usr/bin/python3

from prettytable import PrettyTable
    
x = PrettyTable()

x.field_names = ["City name", "Area", "Population", "Annual Rainfall"]

x.align["City name"] = "l"#如果不指示某些特定的列就对所有的如x.align='l'#将会对所有的行
x.align["Area"] = "r"
x.align["Annual Rainfall"] = "r"

x.add_row(["Adelaide", 1295, 1158259, 600.5])
x.add_row(["Brisbane", 5905, 1857594, 1146.4])
x.add_row(["Darwin", 112, 120900, 1714.7])
x.add_row(["Hobart", 1357, 205556, 619.5])
x.add_row(["Sydney", 2058, 4336374, 1214.8])
x.add_row(["Melbourne", 1566, 3806092, 646.9])
x.add_row(["Perth", 5386, 1554769, 869.4])

print(x)
#输出
$ ./alignment.py 
+-----------+------+------------+-----------------+
| City name | Area | Population | Annual Rainfall |
+-----------+------+------------+-----------------+
| Adelaide  | 1295 |  1158259   |           600.5 |
| Brisbane  | 5905 |  1857594   |          1146.4 |
| Darwin    |  112 |   120900   |          1714.7 |
| Hobart    | 1357 |   205556   |           619.5 |
| Sydney    | 2058 |  4336374   |          1214.8 |
| Melbourne | 1566 |  3806092   |           646.9 |
| Perth     | 5386 |  1554769   |           869.4 |
+-----------+------+------------+-----------------+

　　

get_string()方法、控制表显示什么

　　这个方法返回 里面的参数对当前表的影响，他有几个选项来控制table怎样显示

　　title参数为输出的表加上名字

---snip---
print(x.get_string(title="Australian cities"))#就是在print里面

#输出
$ ./table_title.py 
+-------------------------------------------------+
|                Australian cities                |
+-----------+------+------------+-----------------+
| City name | Area | Population | Annual Rainfall |
+-----------+------+------------+-----------------+
|  Adelaide | 1295 |  1158259   |      600.5      |
|  Brisbane | 5905 |  1857594   |      1146.4     |
|   Darwin  | 112  |   120900   |      1714.7     |
|   Hobart  | 1357 |   205556   |      619.5      |
|   Sydney  | 2058 |  4336374   |      1214.8     |
| Melbourne | 1566 |  3806092   |      646.9      |
|   Perth   | 5386 |  1554769   |      869.4      |
+-----------+------+------------+-----------------+

　　fields参数能选择那些列将要被显示出来

---snip---
print(x.get_string(fields=["City name", "Population"]))
#输出
$ ./select_columns.py 
+-----------+------------+
| City name | Population |
+-----------+------------+
|  Adelaide |  1158259   |
|  Brisbane |  1857594   |
|   Darwin  |   120900   |
|   Hobart  |   205556   |
|   Sydney  |  4336374   |
| Melbourne |  3806092   |
|   Perth   |  1554769   |
+-----------+------------+

　　

　　通过start和end参数，我们能选择那些行将要被显示出来

---snip---
print(x.get_string(start=1, end=4))
#输出
$ ./select_rows.py 
+-----------+------+------------+-----------------+
| City name | Area | Population | Annual Rainfall |
+-----------+------+------------+-----------------+
|  Brisbane | 5905 |  1857594   |      1146.4     |
|   Darwin  | 112  |   120900   |      1714.7     |
|   Hobart  | 1357 |   205556   |      619.5      |
+-----------+------+------------+-----------------+

　　PrettyTable还可以通过CSV、database cursor HTML 导入数据、输出数据到HTMl，参见：http://zetcode.com/python/prettytable/

　　

错误

　　*）TypeError: add_row() missing 1 required positional argument: 'row'

(sort) λ python some_sort.py
Traceback (most recent call last):
  File "some_sort.py", line 1327, in <module>
    compared_all(collection,*func_list)
  File "some_sort.py", line 1288, in compared_all
    x.add_row(['1','2'])
TypeError: add_row() missing 1 required positional argument: 'row'

　　因为在创建对象的时候的语句写错了

    x=PrettyTable#这里写错了
    x=PrettyTable()