Python help needed on a loop with multiple variables

April 23, 2022

Basically I want to iterate 5 times through a list of two variables and populate the output iteratively. I’m probably not describing that well enough, so I’ll show what I’m trying to get. I will have a multi-line query in the query2 variable, but I simplified it a bit for the question here.

Here is the code I’m working on:

systems = ["prd1", "prd2", "frz1", "frz2", "dev"]
qgsystems = ["Prd1_v2", "Prd2_v2", "Frz1_v2", "Frz2_v2", "Devl_v2"]
query2 = f"""{{fn blah({x}_1_output.csv)}}select {y};"""
for x, y in zip(systems, qgsystems):
    print(query2)

The output I’m trying to get would be this:

{fn blah(prd1_1_output.csv)}select Prd1_v2;
{fn blah(prd2_1_output.csv)}select Prd2_v2;
{fn blah(frz1_1_output.csv)}select Frz1_v2;
{fn blah(frz2_1_output.csv)}select Frz2_v2;
{fn blah(dev_1_output.csv)}select Devl_v2;

But instead I’m getting this:

{fn blah(dev_1_output.csv)}select Devl_v2;
{fn blah(dev_1_output.csv)}select Devl_v2;
{fn blah(dev_1_output.csv)}select Devl_v2;
{fn blah(dev_1_output.csv)}select Devl_v2;
{fn blah(dev_1_output.csv)}select Devl_v2;

What am I doing wrong?

When I start a fresh session, I get closer to what’s wrong. But I’m kinda stuck still.

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-1-3ea2eb0d6f53> in <module>
      1 systems = ["prd1", "prd2", "frz1", "frz2", "dev"]
      2 qgsystems = ["Prd1_v2", "Prd2_v2", "Frz1_v2", "Frz2_v2", "Devl_v2"]
----> 3 query2 = f"""{{fn blah({x}_1_output.csv)}}select {y};"""
      4 for x, y in zip(systems, qgsystems):
      5     print(query2)

NameError: name 'x' is not defined

>Solution :

systems = ["prd1", "prd2", "frz1", "frz2", "dev"]
qgsystems = ["Prd1_v2", "Prd2_v2", "Frz1_v2", "Frz2_v2", "Devl_v2"]
query2 = "{{fn blah({x}_1_output.csv)}}select {y};"
for x, y in zip(systems, qgsystems):
    print(query2.format(x=x, y=y))