[英]Python iterate over a dictionary
In [26]: test = {}
In [27]: test["apple"] = "green"
In [28]: test["banana"] = "yellow"
In [29]: test["orange"] = "orange"
In [32]: for fruit, colour in test:
....: print fruit
....:
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
/home1/users/joe.borg/<ipython-input-32-8930fa4ae2ac> in <module>()
----> 1 for fruit, colour in test:
2 print fruit
3
ValueError: too many values to unpack
我想要的是迭代测试并获得密钥和值。 如果我只是for item in test:
我只获得密钥。
最终目标的一个例子是:
for fruit, colour in test:
print "The fruit %s is the colour %s" % (fruit, colour)
在Python 2中你会做:
for fruit, color in test.iteritems():
# do stuff
在Python 3中,使用items()
代替( iteritems()
已被删除):
for fruit, color in test.items():
# do stuff
本教程将介绍这一点。
更改
for fruit, colour in test:
print "The fruit %s is the colour %s" % (fruit, colour)
至
for fruit, colour in test.items():
print "The fruit %s is the colour %s" % (fruit, colour)
要么
for fruit, colour in test.iteritems():
print "The fruit %s is the colour %s" % (fruit, colour)
通常情况下,如果你遍历一个字典,它只会返回一个键,所以这就是它错误地说“解压缩的值太多”的原因。 相反, items
或iteritems
将返回key value pair
list of tuples
或iterator
以迭代key and values
。
或者,您始终可以通过键访问该值,如以下示例所示
for fruit in test:
print "The fruit %s is the colour %s" % (fruit, test[fruit])
for key in mydict
遍历键。 您想要迭代项目:
for fruit, colour in test.iteritems():
print "The fruit %s is the colour %s" % (fruit, colour)
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