July 2017
Intermediate to advanced
398 pages
11h 54m
Chinese
Content preview from Python数据处理
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供机器读取的数据
｜
41
无论是我们正在写的代码，还是我们将面对的许多其他问题，解决问题的方法往往不止一
种。
csv.reader()
返回的是一个数据的列表，里面包含的是文件中的每一行数据，在我们刚
开始处理问题时，这是一个很容易理解的方法。下面要对脚本做少许修改，将列表行改成字
典行。这样在我们探索数据集的过程中，读取数据、对比数据和理解数据会变得更加容易。
在文本编辑器中，将第
4
行
reader = csv.reader(csvfile)
修改成
reader = csv.
DictReader(csvfile)
。现在你的代码应该是这样的：
import
csv
csvfile = open('data-text.csv', 'rb')
reader = csv.DictReader(csvfile)
for
row
in
reader:
print
row
保存文件并重新运行，每一个数据记录变成一个字典。字典的键来自于
CSV
文件的第一
行。后面所有行都是字典的值。下面是一行数据对应的输出：
{
'Indicator': 'Healthy life expectancy (HALE) at birth (years)',
'Country': 'Zimbabwe',
'Comments': '',
'Display Value': '49',
'World Bank income group': 'Low-income',
'Numeric': '49.00000',
'Sex': ...
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