python学习之创建和使用字典

# dict函数
items = [("dddd","fdfd"),("age", 42)];
d = dict(items);
print(d);

d = dict(name = 'ddddd', age = 'jldjlf');
print(d);

print(len(d));

print(d['name']);
d['aaa'] = 'bbbbb';

print(d);

# clear 方法

d.clear();
print(d);

# copy方法

d = dict(name = 'ddddd', age = 'jldjlf', addr = 'aaa');

y = d.copy();

print(y);

# get方法
print(d.get('name'));

#pop 和popitem

d.pop('name');
print(d);
d.popitem();
print(d);

# has_key
de = dict();

print(de.has_key('name'));

de['name'] = 'eric';
print(
de.has_key('name'));

# values 和 itervalues

di = {};

di[1] = 1;

di[2] = 2;

di[3] = 3;
di[4] = 4;

print(di.values());

from math import pi;
print(pi);