Python中的字典理解

Question

有没有办法解决字典理解问题？bmcdsreg = {}for key, val in bms.iteritems():    bmcdsreg[key] = {}    for reg in bmmaps.columns:        bmcdsreg[key][reg]= val*bmmaps[reg]我有以下密钥互换的版本：bmcdsreg = {reg: {key: val*bmmaps[reg] for key, val in bms.iteritems()}             for reg in bmmaps.columns}

Answer 1

方法如下：

bmcdsreg = {

    key: {reg: val * bmmaps[reg] for reg in bmmaps.columns}

    for key, val in bms.items()

}