[英]How to Write Header only once in Python
我对编程很陌生,我怎么能只写一次 header 但其他值重复我不知道用什么术语来描述这个,所以我会告诉你我的意思:
toWriteHeader = [
["Timestamp:", "Overall result:","Blank", "Soll-orderno:", "Desired-HW-Version:", "Desired-SF-Version:","Desired-productcode:", "Desired-device-type:", "Scancode:", "Wbm-orderno:", "Wbm-HW-Version:", "Wbm-SF-Version:",
"Wbm-mac-address:","combined-product-code:", "wbm-device-type:"],
]
toWrite = [
[now ,"Blank",d_ordernum,d_hw_version,d_sf_version,pc_praefix,d_dev_typ,scancode_string,ord_nmr,ord_nmr,v,b]
]
file = open('Test.csv', 'w')
with file:
writer = csv.writer(file)
for row in toWriteHeader:
writer.writerow(row)
file = open('Test.csv', 'a')
with file:
writer = csv.writer(file)
for row in toWrite:
writer.writerow(row)
所以基本上“writeToHeader”只需要写一次,但其他值需要重复附加,但这不会发生我只写一次“toWrite”
任何人都可以建议安迪解决方案或给我看一个例子。 PS:go 对我来说容易,我是初学者
示例 output 到文件:
Timestamp:, Overall result:,Soll-orderno:,Desired-HW-Version:,Desired-SF-Version:,Desired-productcode:,Desired-device-type:,Scancode:,Wbm-orderno:,Wbm-HW-Version:,Wbm-SF-Version:,Wbm-mac-address:,combined-product-code:,wbm-device-type:
2021-04-26 13:32:11,Blank,58184,1.00,1.0.0,7A2F7,TREE M-5TX PN IP67,58183#99AF0M000F9EF41A80,58184,58184,1.00,1.0.0
2021-04-26 13:32:32,Blank,58184,1.00,1.0.0,7A2F7,TREE M-5TX PN IP67,58183#99AF0M000F9EF41A80,58184,58184,1.00,1.0.0
2021-04-26 13:32:38,Blank,58184,1.00,1.0.0,7A2F7,TREE M-5TX PN IP67,58183#99AF0M000F9EF41A80,58184,58184,1.00,1.0.0
2021-04-26 13:33:48,Blank,58184,1.00,1.0.0,7A2F7,TREE M-5TX PN IP67,58183#99AF0M000F9EF41A80,58184,58184,1.00,1.0.0
2021-04-26 13:33:55,Blank,58184,1.00,1.0.0,7A2F7,TREE M-5TX PN IP67,58183#99AF0M000F9EF41A80,58184,58184,1.00,1.0.0
我当前的 Output 到文件:
Timestamp:, Overall result:,Soll-orderno:,Desired-HW-Version:,Desired-SF-Version:,Desired-productcode:,Desired-device-type:,Scancode:,Wbm-orderno:,Wbm-HW-Version:,Wbm-SF-Version:,Wbm-mac-address:,combined-product-code:,wbm-device-type:
2021-04-26 13:32:11,Blank,58184,1.00,1.0.0,7A2F7,TREE M-5TX PN IP67,58183#99AF0M000F9EF41A80,58184,58184,1.00,1.0.0
这样的事情有帮助吗?
import csv
toWriteHeader = [
["Timestamp:", "Overall result:","Blank", "Soll-orderno:", "Desired-HW-Version:", "Desired-SF-Version:","Desired-productcode:", "Desired-device-type:", "Scancode:", "Wbm-orderno:", "Wbm-HW-Version:", "Wbm-SF-Version:",
"Wbm-mac-address:","combined-product-code:", "wbm-device-type:"],
]
toWrite = [
['now' ,"Blank",'d_ordernum','d_hw_version','d_sf_version','pc_praefix','d_dev_typ','scancode_string','ord_nmr','ord_nmr','v','b']
]
with open('Test.csv', 'w') as f:
writer = csv.writer(f)
writer.writerows(toWriteHeader)
for row in range(10):
writer.writerows(toWrite)
您需要将toWrite
值调整回变量和for row
部分。但这会在 csv 中放置一个“标题”,然后是数据行。
我假设您想多次运行该程序并且“toWrite”列表中的值发生变化?
如果是这样,您的问题是您总是执行该部分:
file = open('Test.csv', 'w')
with file:
writer = csv.writer(file)
for row in toWriteHeader:
writer.writerow(row)
因此,您以覆盖现有内容的模式“w”打开文件。 只需在编写 header 之前检查文件是否存在。 此外,最好将文件作为上下文管理器(with)的一部分打开,以便之后自动关闭:
import os.path
fname = 'HERE SHOULD BE THE FULL PATH OF THE FILE'
if (not os.path.isfile(fname)):
with open(fname, 'w') as file:
writer = csv.writer(file)
for row in toWriteHeader:
writer.writerow(row)
您必须先在 fname 中定义文件的完整路径,或者先更改到文件的目录。
此解决方案假定您第一次运行代码以编写 header 时该文件不存在。 如果它可能已经存在但可能为空,您可以检查它是否为空: How to check if.xls and.csv files are empty
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