appending values to create 2d array

Question

I have a text file with 3240 rows and 1 column of values. Every 81 values represents one layer in a 2-D framework. So after 81 values, I would reach z=2, then 162, z=3 and so forth until then end (should be 40 x levels). I want to append the values in this text file to create a 2-D array, that basically represents a value at a specific (x,z) point. Here's what I have:

 df = pd.read_excel("/nfs/home11/grad/2017/et654149/ATM562/HW3/HW3atm562.xlsx")
 pivals=df.as_matrix()
 pi=[]
 l=np.arange(0, 3320, 41)
 count=0
 i=0
 for i in range(len(l)):
         pi[0][i].append(pivals[i])
         count=count+1

I keep getting the error "list index out of range" and honestly I have no idea if what I'm trying to accomplish is even correct with the code I am using. Eventually I want to plot this value on a contour filled plot.

Edit: I've tried using reshape before and after the comment below, but I am getting the error "index 40 is out of bounds for axis 1 with size 1".

This code works, but I after trying to simply plot this now on a contour plot, I am getting this error: ValueError: setting an array element with a sequence. — Eli Turasky
– Eli Turasky, Commented Oct 23, 2018 at 18:31

B. Cratty · Accepted Answer · 2018-10-23 18:25:49Z

2

After investigate a multitude of errors here is a solution:

x = 40 
y=81 
z=[[0 for row in range(0,x)] for col in range(0,y)] 
for i in range(x): 
      for j in range(y): 
           z.append(pivals[i+j])
a = array(z)
a = a.reshape(81, 41)

edited Oct 23, 2018 at 18:25

answered Oct 23, 2018 at 16:08

B. Cratty

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8 Comments

Eli Turasky Over a year ago

'numpy.ndarray' object is not callable is the error I get. Tried putting np.reshape(pivals [81, 40]) and get "index 40 is out of bounds for axis 1 with size 1".

B. Cratty Over a year ago

All you did was run the code that I provided right? @EliTurasky

Eli Turasky Over a year ago

Yes, I simply ran what you provided.

B. Cratty Over a year ago

Try converting the matrix to an array before by using np.asarray(pivals) before calling reshape

Eli Turasky Over a year ago

The as_matrix already makes pivals an array. That's why in my original comment I tried using brackets instead of parentheses (which I think you are supposed to since it is an array). However, doing this results in the error I posted above.

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