How to continue after the return command in python?

Question

Imagine we have a piece of code which cuts the large data into smaller data and do some process on it.

def node_cut(input_file):
    NODE_LENGTH = 500
    count_output = 0
    node_list=[]

    for line in input_file.readlines():
        if len(node_list) >= NODE_LENGTH :
            count_output += 1   
            return( node_list,count_output )
            node_list=[]  

        node,t=line.split(',')
        node_list.append(node) 

if __name__ =='__main__':

    input_data = open('all_nodes.txt','r')
    node_list, count_output = node_cut(input_data)
    some_process(node_list)

while node_cut return the first data list, the for loop stop going on for the rest of the large data. How I can make sure that it returns but still the loop continues?

score 7 · Accepted Answer · answered Oct 25 '11 at 10:05

Use yield:

def node_cut(input_file):
    NODE_LENGTH = 500
    count_output = 0
    node_list=[]

    for line in input_file.readlines():
        if len(node_list) >= NODE_LENGTH :
            count_output += 1   
            yield( node_list,count_output )
            node_list=[]  

        node,t=line.split(',')
        node_list.append(node) 

if __name__ =='__main__':
    with open('all_nodes.txt','r') as input_data:
      for node_list, count_output in node_cut(input_data):
        some_process(node_list)

Thanks for loop was a great advice! – masti Oct 25 '11 at 14:22 — masti, Oct 25 '11 at 14:22

score 5 · Answer 2 · edited May 23 '17 at 10:34

5

Use yield instead of return. See this question or this (somewhat old) article for how it works.

edited May 23 '17 at 10:34

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answered Oct 25 '11 at 10:04

Fred Foo

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How to continue after the return command in python?

2 Answers2