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()
