How do I get a variable inside of an "if" statement to be a global variable?-CodePudding

I'm new to Python, and I need to get the new DataFrame with the appended values (df_ap) after the condition is met, is this possible or should I try a completely new approach.

This is my current code:

df = pd.DataFrame(columns=["C1", "C2", "C3"])
Var1 = input("Input ")

if Var1 == 1:
 df_ap = df.append({"C1": 100, "C2": 200, "C3":300}, ignore_index=True)

print(df)
print(df_ap)

Output:

Input 1
Empty DataFrame
Columns: [C1, C2, C3]
Index: []
NameError: name 'df_ap' is not defined

CodePudding user response：

Var_1 is a string not an integer so you have to cast as int or compare it with a string:

Var1 = int(input("Input "))

if Var1 == 1:

Or:

Var1 = input("Input ")

if Var1 == "1":

CodePudding user response：

Try creating the definition outside the if.

df = pd.DataFrame(columns=["C1", "C2", "C3"])
Var1 = input("Input ")

df_ap = None

if Var1 == 1:
    df_ap = df.append({"C1": 100, "C2": 200, "C3":300}, ignore_index=True)

print(df)
print(df_ap)

CodePudding user response：

First, in order to make your condition working, you need to make sure your input has been converted into int before the if condition. Since you using df_ap outside of the if condition, you have to define it outside the if as well, which is before the condition execution.

import pandas as pd

df = pd.DataFrame(columns=["C1", "C2", "C3"])
df_ap = pd.DataFrame()

Var1 = int(input("Input "))

if Var1 == 1:
 df_ap = df.append({"C1": 100, "C2": 200, "C3":300}, ignore_index=True)

print(df)
print(df_ap)

Another way, you can simply reuse df, since it has been defined outside if condition:

import pandas as pd

df = pd.DataFrame(columns=["C1", "C2", "C3"])

Var1 = int(input("Input "))

if Var1 == 1:
 df = df.append({"C1": 100, "C2": 200, "C3":300}, ignore_index=True)

print(df)