equalize length of the temp data - pandas

Question

I have two text files(file1.txt,file2.txt) that contain time_stamp in julian day in first column and temperature data in second columns. Based on the time stamp of file1.txt I have to extend the length of file2.txt by appending zero, so that the length of the file2.txt will be equals to length of the file1.txt.
Input data
cat file1.txt
023 4.5
024 6.8
025 9.8
030 2.3
125 1.4
129 5.8
168 1.0
cat file2.txt
024 1.2
025 2.3
125 1.6
output
023 0.0
024 1.2
025 2.3
030 0.0
125 1.6
129 0.0
168 0.0
In my code i am unable to insert the main portion that does the magic
I tried
import numpy as np
import pandas as pd
data1=np.loadtxt("data1.txt")
data2=np.loadtxt("data2.txt")
if data1==data2:
print('same length data')
else:
............

Answer 1

You can try this in awk:
awk 'FNR==NR{
f2[$1]=$0
next
}
$1 in f2{print f2[$1]; next}
{printf("%s%s%1.1f\n", $1, OFS, 0.0)}
' file2 file1
Or this in Python:
f2_data={}
with open(fn2) as f2:
for line in f2:
line=line.strip()
field1, field2=line.split()
f2_data[field1]=line
with open(fn1) as f1:
for line in f1:
field1, field2=line.strip().split()
if field1 in f2_data:
print(f2_data[field1])
else:
print(field1, '0.0')
Either prints:
023 0.0
024 1.2
025 2.3
030 0.0
125 1.6
129 0.0
168 0.0
In both cases the strategy is the same:
Make an index of file2 first to see what gets printed from that file;
Print the julian date and 0.0 to fill in for date not in file2