如何将字段添加到dbf文件？

Question

我有这样的事情：

from dbfpy import dbf
import random

db = dbf.Dbf('DMWWGS84/DMAWGS84.dbf',new=False)
db.addField(("Data","D"))
for record in db:
    print record
    record["Data"]=random.random()
db.close()

但它抱怨：

Traceback (most recent call last):
  File "merge_csv.py", line 5, in <module>
    db.addField(("Data","D"))
  File "/Users/alex/anaconda2/lib/python2.7/site-packages/dbfpy/dbf.py", line 246, in addField
    raise TypeError("At least one record was added, "
TypeError: At least one record was added, structure can't be changed

它在谈论什么记录？ 这是这样做的好方法吗？

Answer 1

改用我的dbf库：

pip安装dbf

（您可能需要先pip install enum34 ）

然后命令：

# lightly tested

import dbf
import random

db = dbf.Table('whatever.dbf')
with db:
    db.add_fields('data N(12,7)')
    for record in db:
        dbf.write(record, data=random.random())

注意 ：将随机数写入日期字段将无法正常工作。

Answer 2

该答案中有一个错误，您应该在使用文件之前打开该文件：

import dbf
import random

db = dbf.Table('whatever.dbf')
db.open()
with db:
    db.add_fields('data N(12,7)')
    for record in db:
        dbf.write(record, data=random.random())