一、if判断语句
from flask import Flask,render_template
app = Flask(__name__)
@app.route("/control")
def control():
age = 10
return render_template("control.html",age=age)
if __name__ == '__main__':
app.run(debug=True,host="0.0.0.0",port=8000)
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>if判断语句</title>
</head>
<body>
{% if age>18 %}
<div>您{{age}}岁了，可以单独进入网吧啦！</div>
{% elif age==18 %}
<div>您刚刚{{age}}岁,需要成年人陪同进入网吧！</div>
{% else %}
<div>您才{{age}}岁，不能进入网吧！</div>
{% endif %}
</body>
</html>
二、for循环语句
Jinja2模版的for循环不存在break和continue来判断循环的语句，这个是和Python最大的区别，另外jinja2中只有for循环，不存在while循环
from flask import Flask,render_template
app = Flask(__name__)
@app.route("/for")
def forx():
books = [{
"name":"三国演义",
"author":"罗贯中",
"price":100
},{
"name":"水浒传",
"author":"施耐庵",
"price":30
}]
return render_template("forxunhuan.html",books=books)
if __name__ == '__main__':
app.run(debug=True,host="0.0.0.0",port=8000)
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>for循环语言演示</title>
</head>
<body>
{% for book in books%}
<div>{{loop.index}}：书名：{{book.name}},作者：{{book.author}},价格：{{book.price}}</div>
{% endfor %}
</body>
</html>
