在 Python 中使用 If 语句调用函数答案

【问题标题】：Using If statement to call a functions in Python在 Python 中使用 If 语句调用函数
【发布时间】：2020-06-09 22:45:55
【问题描述】：

我正在运行一个代码来创建 cloudformation 堆栈、删除堆栈、使用 python 使用 json 文件使用定义的参数变量更新堆栈。

我在 init() 函数下定义了 3 个不同的语句。我需要设置一个 if 条件：如果我想创建一个堆栈，它将调用“create_products” 否则，更新堆栈，它将调用“update_products” elif，删除一个堆栈，它将更新“delete_products”

from __future__ import print_function
import subprocess
import json
import yaml
import sys
import os
import re
import boto3
from glob import glob

def createstack(productName, productId, paramlist): 
    try:
        client = boto3.client('servicecatalog', region_name='us-east-1')
        ProvisioningArtifactId = client.list_provisioning_artifacts(ProductId=productId)
        ArtifactId = ProvisioningArtifactId['ProvisioningArtifactDetails'][0]['Id']
        response = client.provision_product(ProvisionedProductName=productName, ProductId=productId, ProvisioningArtifactId=ArtifactId, ProvisioningParameters=paramlist)
        print(response)
    except Exception as e:
        error = "An error occurred processing this request: " + str(e)
        print(error) 

def updatestack(productName, productId, paramlist):    
    try:
        client = boto3.client('servicecatalog', region_name='us-east-1')
        ProvisioningArtifactId = client.list_provisioning_artifacts(ProductId=productId)
        ArtifactId = ProvisioningArtifactId['ProvisioningArtifactDetails'][0]['Id']
        response = client.update_provisioned_product(ProvisionedProductName=productName, ProductId=productId, ProvisioningArtifactId=ArtifactId, ProvisioningParameters=paramlist)
        print(response)
    except Exception as e:
        error = "An error occurred processing this request: " + str(e)
        print(error)

def deletestack(productName):
    try:
        client = boto3.client('servicecatalog', region_name='us-east-1')
        response = client.terminate_provisioned_product(ProvisionedProductName=productName)
        print(response)
        return response
    except Exception as e:
        error = "An error occurred processing this request: " + str(e)
        return(error)

def init():
    #global args
    with open("list_provisional_product.json") as f:
        product_list = json.load(f)
    with open("testing-pipeline-params.json") as f:
        baselist = json.load(f)

    for product in product_list["update_products"]:
        for provisioned_product_name in product["provisioned_product_names"]:
            updatestack(productName=provisioned_product_name, productId=product["product_id"], paramlist=baselist[provisioned_product_name])

    for product in product_list["delete_products"]:
        for provisioned_product_name in product["provisioned_product_names"]:
            deletestack(productName=provisioned_product_name)

    for product in product_list["create_products"]:
        for provisioned_product_name in product["provisioned_product_names"]:
            createstack(productName=provisioned_product_name, productId=product["product_id"], paramlist=baselist[provisioned_product_name])


def main():
    init()
if __name__== "__main__": 
    main()

【问题讨论】：

标签： python for-loop if-statement while-loop boto3

【解决方案1】：

是的，您必须通过命令行参数从用户那里获取操作名称（创建/更新/删除），或者在代码执行期间通过input 函数询问用户。

Demo 1：使用sys.argv从命令行参数获取操作名运行 python 代码时，您必须提供操作名称。这里 Py 文件名是if_loop.py

import sys
print("arg:", sys.argv)

try:
    operation_name = sys.argv[1].lower()
except IndexError:
    print("Argument is missing")
    exit()

if operation_name == "create":
    print("Call Create function")
elif operation_name == "update":
    print("Call Update function")
elif operation_name == "delete":
    print("Call Dale function")
else:
    print("Invalid Operation name")

输出

Invalid Operation name
(env) PS C:\Users\vivek\Documents\Workplace\stackoverflow> python .\if_loop.py Create
arg: ['.\\if_loop.py', 'Create']
Call Create function

演示2：使用input函数

operation_name = input("Give Operation Name:").lower()
if operation_name == "create":
    print("Call Create function")
elif operation_name == "update":
    print("Call Update function")
elif operation_name == "delete":
    print("Call Dale function")
else:
    print("Invalid Operation name")

输出

Give Operation Name:Update
Call Update function

【讨论】：

【解决方案2】：

非常感谢维韦克！我宁愿采用第一种方法，即 argv，它实际上是根据我的需要工作的！太棒了

【讨论】：