milenko - 8 months ago 207

Python Question

I have my code

`import numpy as np`

a1=np.empty(10)

a1.fill(1900)

a2=np.empty(10)

a2.fill(3100)

a3=np.empty(10)

a3.fill(3600)

with open('homes.txt', 'w') as f:

for i in a1:

for j in a2:

for k in a3:

np.savetxt(f, i, j,k)

I want to write arrays to text file like this

`1900. 3100. 3600.`

1900. 3100. 3600.

1900. 3100. 3600.

But terminal gives me

`Traceback (most recent call last):`

File "m84.py", line 16, in <module>

np.savetxt(f, i, j,k)

File "/usr/lib/python2.7/dist-packages/numpy/lib/npyio.py", line 1034, in savetxt

ncol = X.shape[1]

IndexError: tuple index out of range

If my idea is wrong it would be nice that someone proposes other solution.

Answer

You can do this by writing to the file normally:

```
with open('homes.txt', 'w') as f:
for i in a1:
for j in a2:
for k in a3:
f.write("%f %f %f\n"%(i,j,k))
```

However, I am suspecting that you don't really want to do exactly this, because this will print 1000 lines (because of the nested loops). If you just want to write the arrays in a file, with each value being written once you can use `savetxt`

, and you don't need to place it inside a loop. It can write a whole array at once, so you could do it as follows:

```
a = np.empty(shape = (10,3))
a[:,0].fill(1900)
a[:,1].fill(3100)
a[:,2].fill(3600)
np.savetxt("homes.txt",a)
```