「一个奇怪的 Python CSV 处理问题」的评论

评论者：ziv2013

ziv2013 — Sat, 04 Apr 2020 00:45:08 +0000

回复给 krishna。专业啊

评论者：krishna

krishna — Fri, 03 Apr 2020 08:00:10 +0000

//分享另一种解法，使用flex(或者antlr)，以下是mylex.flex的内容：
%OPTION noyywrap
%{
#define ECHO
%}
%%
[0-9]{2}”:”[0-9]{2}”:”[0-9]{2}”.”[0-9]+” “([A]|[P])[M] {printf(“time is: %s\n”,yytext);}
%%
int main()
{
while(yylex())
{
//nothing;
}
return 0;
}

//以下是测试输出：
E:\temp\test>flex –wincompat mylex.flex

E:\temp\test>cl lex.yy.c
Microsoft (R) C/C++ Optimizing Compiler Version 19.15.26730 for x64
Copyright (C) Microsoft Corporation. All rights reserved.

lex.yy.c
Microsoft (R) Incremental Linker Version 14.15.26730.0
Copyright (C) Microsoft Corporation. All rights reserved.

/out:lex.yy.exe
lex.yy.obj

E:\temp\test>type DataX.CSV | lex.yy.exe
time is: 10:21:22.8436230 PM
time is: 10:21:22.8436625 PM
time is: 10:21:22.8436974 PM
time is: 10:21:22.8440542 PM
time is: 10:21:22.8440997 PM
time is: 10:21:22.8441291 PM
time is: 10:21:22.8442544 PM

//flex可以在这里下载：https://sourceforge.net/projects/winflexbison/

评论者：Simon

Simon — Wed, 25 Mar 2020 14:42:59 +0000

import csv, os

try:
import chardet
except ModuleNotFoundError:
raise Error(“Please install chardet by \”pip install chardet\” first.”)

def checkEncoding(file):
bytes = min(32, os.path.getsize(file))
raw = open(file, ‘rb’).read(bytes)
result = chardet.detect(raw)
encoding = result[‘encoding’]
return encoding

with open(‘Datax.CSV’, encoding=checkEncoding(‘Datax.CSV’)) as csvfile:
reader = csv.DictReader(csvfile)
for row in reader:
print(row[‘Time of Day’])