Python help needed on a loop with multiple variables-CodePudding

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

CodePudding user response：

You can't define the string outside of the loop at expect it to get filled in when printing it inside. Instead you'll have to build the string inside the loop:

systems = ["prd1", "prd2", "frz1", "frz2", "dev"]
qgsystems = ["Prd1_v2", "Prd2_v2", "Frz1_v2", "Frz2_v2", "Devl_v2"]

for x, y in zip(systems, qgsystems):
    print(f"{{fn blah({x}_1_output.csv)}}select {y};")

Output:

{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;

CodePudding user response：

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))