Adding 2 hours to all lines in CSV file - CentOS

Question

I have a CSV file in the following format

YYYY-mm-dd HH:MM:SS     Some commentary text 
YYYY-mm-dd HH:MM:SS     Some commentary text 
YYYY-mm-dd HH:MM:SS     Some commentary text 
YYYY-mm-dd HH:MM:SS     Some commentary text 

etc.

How can I add 2 hours to each date entry? I know the date is going to be in the first 19 characters in each line.

Answer 1

快速而肮脏的解决方案：

while read line ; do OldDate="$(echo "$line"| awk '{print $1" "$2}')" ; NewDate=$(date "+%Y-%m-%d %H:%M:%S" -d "$OldDate +2 hours"); echo "$line" | sed "s/$OldDate/$NewDate/g"   ; done < original.csv > modified.csv

Answer 2

awk -v "DecalHour=2" '
     {
     OldString = substr( $0, 20)

     OldTime = substr( $0, 1, 19)
     gsub( /[^[:digit:]]/, " ", OldTime)
     NewTime = mktime( OldTime ) + DecalHour * 60 * 60
     NewStringTime = strftime( "%Y-%m-%d %H:%M:%S", NewTime)


     # old - new
     #print $0 " -> " NewStringTime OldString
     # only new content
     print NewStringTime OldString
     }
     ' YourFile

Comment:

• This could be a one line (better perf), code is spread with intermediate variable for (self) understanding purpose
• work with gawk, not posix awk (no time function)
• format of time is fixed as your sample
• use the time (epoch) addition (so in sec) to allow day passing (after 21:59:59)

Answer 3

You can do it in Python also

"""input
2017-01-01 12:00:00,Some commentary text 
2017-01-02 12:00:00,Some commentary text 
2017-01-03 12:00:00,Some commentary text 
2017-01-04 12:00:00,Some commentary text 
"""
#said it was a csv, right :-)

import numpy as np
import pandas as pd
df=pd.read_csv("data.csv",names=[0,1])
df[0]=pd.to_datetime(df[0])+np.timedelta64(2,'h')
df.to_csv("/tmp/ans.csv",index=False,header=False)
"""
output looks like this:
2017-01-01 14:00:00,Some commentary text 
2017-01-02 14:00:00,Some commentary text 
2017-01-03 14:00:00,Some commentary text 
2017-01-04 14:00:00,Some commentary text 
"""