我需要向通過 Web 匯入資料創建的 CSV 檔案添加一列。新列必須是兩行的串聯，例如 06_2018。
New_Format_Data = ''
Output_File = open('Desktop/HW3/' state_names[counter] '.txt','w')
for counter in range(0 , len(urls)):#Will go tru all the states.
print (urls[counter])
html = urllib.request.urlopen(urls[counter]).read().decode('utf-8')#opening url
rows = html.splitlines(1)#Split the data in rows. The number 1 is very important
if counter ==0:
New_Format_Data = "Test" rows[0] #Header
for row in range(1, len(rows)): #First row...
New_Format_Data = 'Test' '\t' rows[row]#Adding that state column.
Output_File.write(New_Format_Data)#Once finished with the for loops then the it will download and close.
Output_File.close()
uj5u.com熱心網友回復：
我不知道你在行中有什么 - 以及你想要連接哪些列，所以我以第 1 列和第 2 列為例。
您必須將行（字串）拆分為值串列，然后在此串列中替換/添加值，然后將所有值連接回單個字串，然后您可以寫入新檔案。
它將需要\n從字串的末尾洗掉，因為它需要在同一行中添加新值 - 所以1insplitlines()將無用。
像這樣的東西。
我直接從串列中獲取字串，而不是使用索引和range(len(..))
for row in rows[1:]: # get directly string instead of index
# convert to list
row = row.split(',')
# create new value using column 1 and 2
new_value = row[1] '_' row[2]
# append to list
row.append(new_value)
# convert back to string
row = ','.join(row)
# add new row and `\n` at the end
New_Format_Data = 'Test' '\t' row '\n'
完整代碼可能如下所示
# PEP8: at least two spaces before `#` and one space after `#
new_format_data = '' # PEP8: `lower_case_names` for variables
output_file = open('Desktop/HW3/' state_names[counter] '.txt','w')
for counter, url in enumerate(urls):
print('url:', url)
html = urllib.request.urlopen(url).read().decode('utf-8') # opening url
rows = html.splitlines() # split the data in rows. DON'T NEED `1` because I don't need `\n'
if counter == 0:
new_format_data = "Test" rows[0] ',new_columns' '\n' # header with new column
for row in rows[1:]: # get directly string instead of index
# convert to list
row = row.split(',')
# create new value using column 1 and 2
new_value = row[1] '_' row[2]
# append to list
row.append(new_value)
# convert back to string
row = ','.join(row)
new_format_data = 'Test' '\t' row '\n' # adding that state column.
# --- after loop ---
output_file.write(new_format_data) # once finished with the for loops then the it will download and close.
output_file.close()
但是，如果某些列具有,價值，這可能會出現問題，因為split會將其視為分隔符。所以最好使用csv可以解決所有問題的標準模塊。
就像是
import csv
output_file = open('Desktop/HW3/' state_names[counter] '.txt','w')
# create csv writer
output_csv = csv.writer(output_file)
for counter, url in enumerate(urls):
print('url:', url)
html = urllib.request.urlopen(url).read().decode('utf-8') # opening url
# read all rows from csv
rows = list(csv.reader(html.splitlines()))
if counter == 0:
headers = rows[0]
headers[0] = "Test" headers[0]
headers.append('new_colum')
# write headers
output_csv.writerow(headers)
for row in rows[1:]: # get directly string instead of index
# create new value using column 1 and 2
new_value = row[1] '_' row[2]
# append to row
row.append(new_value)
# write row
output_csv.writerow(row)
# --- after loop ---
output_file.close()
PEP 8——Python 代碼風格指南
uj5u.com熱心網友回復：
它最終像這樣作業：
new_format_data = '' # PEP8: `lower_case_names` for variables
output_file = open('Desktop/HW3_2/' state_names[counter] '.txt','w')
for counter, url in enumerate(urls):
print('url:', url)
html = urllib.request.urlopen(url).read().decode('utf-8') # opening url
rows = html.splitlines() # split the data in rows. DON'T NEED `1` because I don't need `\n'
if counter == 0:
# new_format_data = "Month_Year" '\t' rows[0] '\n' # header with new column
new_format_data = rows[0] "Month_Year" '\n' # header with new column
for row in rows[1:]: # get directly string instead of index
# convert to list
row = row.split('\t')
# create new value using column 1 and 2
new_value = row[2] '_' row[1]
# append to list
row.append(new_value)
# convert back to string
row = '\t'.join(row)
new_format_data = row '\n' # adding that state column.
output_file.write(new_format_data) # once finished with the for loops then the it will download and close.
output_file.close()
我要修改，其實不是txt格式CSV。現在，我正在嘗試洗掉一列并過濾資訊。因此，其中一列是“年”。原始資料從開始1976。2022我只需要來自2015till的資訊2020。嘗試了一些東西，但我破壞了其余的代碼:(
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