[英]How do I go to the first record of a CSV file within the same “for” loop?
我在这里问了一个类似的问题,我得到的答案是使用seek()
方法。 现在我正在做以下事情:
with open("total.csv", 'rb') as input1:
time.sleep(3)
input1.seek(0)
reader = csv.reader(input1, delimiter="\t")
for row in reader:
#Read the CSV row by row.
但是,我想在同一个for循环中导航到CSV的第一条记录。 我知道我的循环不会以这种方式终止,但这正是我想要的。 我不希望for
循环结束,如果它到达最后一条记录,我想导航回第一条记录并重新读取整个文件(并继续阅读)。 我怎么做?
谢谢!
它必须在for
-loop中吗? 您可以像这样(未经测试)实现此行为:
with open("total.csv", 'rb') as input1:
time.sleep(3)
reader = csv.reader(input1, delimiter="\t")
while True:
input1.seek(0)
for row in reader:
#Read the CSV row by row.
为简单起见,创建一个生成器:
def repeated_reader(input, reader):
while True:
input.seek(0)
for row in reader:
yield row
with open("total.csv", 'rb') as input1:
reader = csv.reader(input1, delimiter="\t")
for row in repeated_reader(input1, reader):
#Read the CSV row by row.
我实际上计算了CSV中的总行数,当我在最后一行时,我做了input1.seek(0)
row_count = sum(1 for row in csv.reader(open('total.csv')))
print row_count
row_count2 = 0
with open("total.csv", 'rb') as input1:
time.sleep(3)
input1.seek(0)
reader = csv.reader(input1, delimiter="\t")
for row in reader:
count += 1
#Read the CSV row by row.
if row_count2 == row_count:
row_count2 = 0
time.sleep(3)
input1.seek(0)
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