csv file中的data通常用逗號( , )分隔，但也可以使用其他符號，如 | 、*。
在csv file中如要加入empty string，即標示””即可。
在python中開啟csv file
- use
open()function to open file - read data in the csv file with
csv.reader(), it will create a reader object
-
使用python開啟csv檔時要在
open()function中設定keyword argument來指定換行的格式，如以下data=open(’myfile.csv’, …, newline=”)。 -
example的14-1file.csv內容如下圖
import csv with open("14-1file.csv", newline="", encoding="cp950") as f: csv_data = csv.reader(f) print(csv_data) for row in csv_data: print(row) # <_csv.reader object at 0x0000026E9CD97280> # a reader object # ['id', 'name', 'year of birth'] # ['1', 'albert einstein', '1879'] # ['2', 'isaac newton', '1643'] # ['3', 'marie curie', '1867'] # ['4', 'galilée', '1564'] for row in csv_data: print(row[1].title()) # Name # Albert Einstein # Isaac Newton # Marie Curie # GaliléE
在python寫一個csv檔
- use
open()function with write mode or append mode - use
csv.writer()function to create a writer object
writer.writerow(list)can write a row of datawriter.writerows(list of list)will write several rows of data
import csv
with open("newfile.csv", mode="w", newline="", encoding="cp950") as f:
csv_writer = csv.writer(f, delimiter=",")
csv_writer.writerow(['a', 'b', 'c'])
# in newfile.csv
# a,b,c
import csv
with open("newfile.csv", mode="a", newline="", encoding="cp950") as f:
csv_writer = csv.writer(f, delimiter=",")
csv_writer.writerows([['1', '2', '3'], ['d', 'e', 'f']])
# in newfile.csv
# a,b,c
# 1,2,3
# d,e,f
