Python for loop over matrix

Question

I have a problem with a small python program to cross-match two arrays. As a side note, I'm learning to code in Python in these days, so I assume I'm making some incredibly trivial mistake here. Basically, I want to open two .txt files, create a 2D array from each of them, and compare them to see if they have common elements. So far, I did something like this

#creating arrays from files
models  = np.genfromtxt('models.txt', dtype='float')
data    = np.genfromtxt('data.txt', dtype='float')

#obtaining the number of rows in each array
mod_nrows = models.shape[0]
data_nrows = data.shape[0]

#checking line by line if there are ay matches
for i in range(mod_nrows)
    for j in range(data_nrows)
        do stuff....

but I'm getting the generic error

File "crossmatch.py", line 27
   for i in range(mod_nrows)
                        ^
SyntaxError: invalid syntax

I thought the problem might be that

mod_nrows = models.shape[0]

doesn't return an int (which should be the argument of the function range()), and I tried to change the two for loops to

for i in range(int(mod_nrows))
    for j in range(int(data_nrows))
        do stuff....

but I'm still getting the same error. Any suggestions?

Amarpreet Singh · Accepted Answer · 2017-09-18 14:13:49Z

2

Any for loop should end with a colon (:).

The colon is required primarily to enhance readability. Python docs explicitly mention here

#creating arrays from files
models  = np.genfromtxt('models.txt', dtype='float')
data    = np.genfromtxt('data.txt', dtype='float')

#obtaining the number of rows in each array
mod_nrows = models.shape[0]
data_nrows = data.shape[0]

#checking line by line if there are ay matches
for i in range(mod_nrows):
    for j in range(data_nrows):
        do stuff....

edited Sep 18, 2017 at 14:13

answered Sep 18, 2017 at 14:06

Amarpreet Singh

2,27017 silver badges27 bronze badges

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

Collectives™ on Stack Overflow

Python for loop over matrix

1 Answer 1

Comments

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Related