Python：如何使用DictReader两次？ [英] Python: How do I use DictReader twice?
问题描述
这感觉像一个非常基本的问题，但我不能在其他地方找到它。我是一个开始的Python用户。
This feels like a very basic question, but I can't find any mention of it elsewhere. I'm a beginning Python user.
当我使用DictReader读取数据，然后使用字典，我无法再次引用。例如，使用此代码：
When I read in data using DictReader, and then use the dictionary, I'm unable to reference it again. For example, using this code:
#!/usr/bin/python
import csv
import cgi
import cgitb
cgitb.enable()
print "<head><title>Title</title></head><body>"
f = open("blurbs.csv","rb")
blurbs = csv.DictReader(f, delimiter="\t")
for row in blurbs:
print row
for row in blurbs:
print row
f.close()
print "</body>"
只打印一次blurbs.csv的内容。第二个for row in blurbs：什么也没有。有什么我错过了吗？
Will only print out the contents of blurbs.csv once. The second "for row in blurbs:" does nothing. Is there something I'm missing? How can I make the dictionary into something I can reference repeatedly?
推荐答案
您只需要将文件找回到开头：
You just need to seek the file back to the start:
with open("blurbs.csv","rb") as f:
blurbs = csv.DictReader(f, delimiter="\t")
for row in blurbs:
print row
f.seek(0)
for row in blurbs:
print row
或者，您可以将字典生成包装到一个列表中，然后操作：
Alternatively you can wrap the dictionary generation into a list of dicts and operate on that:
with open("blurbs.csv","rb") as f:
blurbs = list(csv.DictReader(f, delimiter="\t"))
for row in blurbs:
print row
for row in blurbs:
print row
这篇关于Python：如何使用DictReader两次？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
