How to append numpy array inside loop and save to file

Question

I have written below code and at the end I want to append two array in a single buffer. I want to save to text file. Here is my code :

t=0
while(t>=0 and t<len(nav_time)):
  if nav_time[t]>70000 and nav_time[t]<86400:
      one_time=nav_time[t]
     # print one_time
  if nav_time[t]>=0 and nav_time[t]<70000:
      sec_time=nav_time[t]+86400
      #print sec_time
  total_time=np.append(one_time,sec_time)  # only stores two values not all values
  t=t+1

example data

    Nav_time
   86399
86399.20313
86399.40625
86399.60156
86399.80469
0.003574
0.203574
0.403574
0.603574
0.803574
1.003575
1.203575

NumPy and append seldom go in the same sentence. Why not extend a list and create an array at the very end? — cs95
– cs95, Commented Mar 9, 2018 at 2:52
@cᴏʟᴅsᴘᴇᴇᴅ .Would you tell me the step. How to proceed — Poka
– Poka, Commented Mar 9, 2018 at 3:13
Can you provide a minimal reproducible example with expected output? — cs95
– cs95, Commented Mar 9, 2018 at 3:17
I don't want your data, I want an example. Please make up something? — cs95
– cs95, Commented Mar 9, 2018 at 3:21

manoj · Accepted Answer · 2018-03-09 03:27:53Z

1

You can create 2 lists for one_time and sec_time and append them after your for loop.
Here is a sample

t=0
# Create one_time and sec_time as list 
one_time = []
sec_time = []
while(t>=0 and t<len(nav_time)):
  if nav_time[t]>70000 and nav_time[t]<84600:
      one_time.append(nav_time[t])
     # print one_time
  if nav_time[t]>=0 and nav_time[t]<70000:
      sec_time.append(nav_time[t]+86400)
      #print sec_time
  #total_time=np.append(one_time,sec_time)  # only stores two values not all values
  t=t+1

# Concatenating the 2 lists, this will append sec_time after one_time in a single row.
total_time = np.concatenate((one_time, sec_time), 0)

# Saving to fileName.txt. This creates file with 1 column with multiple rows.
np.savetxt('fileName.txt', total_time, fmt='%f')

I hope this helps.

answered Mar 9, 2018 at 3:27

manoj

4202 silver badges6 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

DJK · Accepted Answer · 2018-03-09 03:52:41Z

0

Assuming your dataframe is named nav_time with a column named Nav_time, this will filter your values.

filter1 = nav_time.where(~(nav_time.Nav_time > 84600)).dropna()
filter2 = np.where(filter1 > 70000,filter1,filter1+86400)

np.savetxt('file.txt', filter2)

answered Mar 9, 2018 at 3:52

DJK

9,3424 gold badges28 silver badges41 bronze badges

1 Comment

Poka Over a year ago

@ DJK. In this process I am missing some data

Collectives™ on Stack Overflow

How to append numpy array inside loop and save to file

example data

2 Answers 2

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

example data

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related