python中from是保留字吗？

一、python中from是保留字吗？

python 中的from是保留字，在引用python模块的时候会用到。

二、python中from有什么用？

把其他模块中的变量、函数或类导入到当前python文件，以便使用它们。常见用法：from xxx import yyy

三、Python的from import和import的区别？

假设有一个包名字叫 numpy, 里面有一个函数 zeros

1、 from numpy import zeros 那么你可以直接调用 zeros()函数

2、import numpy.zeros 那么你只能使用全名 numpy.zeros 这就是区别

四、python脚本开头的from Tkinter import *是什么意思？

这是Python导入库文件的语法： from Tkinter的意思就是导入Tkinter，它是一个库，也可以简单称之为类； import *的意思是导入库中所有的类，函数，变量等等信息，这样在调用相关函数或者变量的时候，就不用加Tkinter前缀了。

五、is it comes from 还是is it from？

Is it comes from?是一个错句。因为在这个句子中，同时出现了be动词is和come的单三comes。这是一个语法错误，在英语当中，当谓语部分出现了be动词时，后面的实意动词只有两种形式，一种是现在分词，一种是过去分词。用单三显然是错误的。这个句子我们可以把它改为does it come from？后面的is it from是正确的。

六、from then on from now on的区别？

区别就是两者意思是不一样的具体的不同如下

from then on中文意思是从那时起

She left in 1984 and from then on he lived alone.

from now on中文意思是从现在开始

Perhaps it would be best not to see much of you from now on.

或许从现在开始最好少和你见面。

七、from to和 from through区别？

from through

没有该用法

from to

1. 主要意思

(1) 表示“从……至……”“从……到……”.如：

How far is it from your office to the bank? 从你办公室到银行有多远?

We are removing from London to the country. 我们正从伦敦迁往乡下.

I want a rope that will go from the top window to the ground. 我要一条绳,其长度能自最上一扇窗户垂到地面.

(2) 表示“由……变成……”“将……改为……”.如：

He has moved from acting to film production. 他由演员变成了制片人.

She’s been downgraded from principal to deputy. 她已从校长降为副校长.

He swings from wild optimism to total despair. 他由极其乐观一变而为完全绝望.

The room was converted from a kitchen to a lavatory. 这房间由厨房改成了厕所.

(3) 表示“从一个……到另一个……”“一个……一个地”“逐个……”“挨个……”.如：

These people go from house to house selling goods. 这些人挨家挨户兜售货物.

The ape swung along from branch to branch. 那只猿猴从一根树枝汤到另一根树枝上.

He went from village to village, seeking for work. 他从一个村子到另一个村子,找寻工作.

I like to hop from channel to channel when I watch TV. 我看电视时喜欢不断地换频道.

Migrant workers move from country to country in search of work. 流动工人从一国迁到另一国找寻工作.

The smaller animals can easily leap from tree to tree. 身体较小的动物可以在树丛间轻巧地跳来跳去.

Computer viruses replicate themselves and are passed along from user to user. 计算机病毒可以自我复制,然后由用户传给用户.

2. 主要句法功能

(1) 用作表语

Lunch is from eleven to two. 从十一点到两点开午饭.

Office hours are from 9 am to 5 pm. 办公时间从上午9点到下午5点.

The price range is from $100 to $500. 价格在100美元至500美元之间不等.

In Britain the long vacation is from June to October. 在英国,长的假期是从六月到十月.

The annual range of temperature is from –10℃ to 40℃. 全年的温度较差为零下10度至40度.

(2) 用作状语

She went straight from school to university. 她中学一毕业就马上进了大学.

Salaries are from 10% to 50% higher than in Britain. 薪金比在英国高10%到15%.

The World Cup Final was beamed live from Britain to Japan. 世界杯决赛从英国向日本作了实况转播.

I work from Tuesday to Saturday, and Sunday and Monday are my days off. 我从星期二到星期六工作,星期日和星期一休息.

(3) 用作定语

通常用于名词后作定语.如：

The transition from boyhood to manhood can be a confusing period. 从少年时期向成年时期的转变常是令人困惑的时期.

但有时from…to…结构用于名词前起修饰作用,此时通常可视为from…后（也就介词to之前）省略了一个名词.如：

Norway jumped from ninth to third place. 挪威从第9位跃升至第3位.（可视为ninth的后面省略了place）

Water passes from a liquid to a solid state when it freezes. 水结冰是由液态变为固态.（可视为liquid的后面省略了state）

Could you cut your essay from 10,000 to 5,000 words? 请把你的那篇文章从10,000字删减到5,000字行吗?（可视为10,000的后面省略了words）

3. 连用名词时是否用冠词

当from…to…用于连接两个名词时,有时名词前需带有冠词,有时不用,情形比较复杂,大致遵循的原则如下：

(1) 若所搭配的名词意思比较具体,是在谈论特定场合的具体人或事物,则通常要用冠词.如：

The book fell from the table to the floor. 书从桌上掉到地板上.

The scene cuts from the shop to the street. 镜头从商店转换到街道.

A bus transported us from the airport to the city. 一辆公共汽车把我们从机场送到市区.

(2) 若所搭配的名词意思比较抽象,只是在谈论一般概念或一般规律等,则不用冠词.比较：

This skill wasn’t handed down from the father to the son. 这项技术并没有从父亲传给儿子.

These skills used to be handed down from father to son. 这些技术以往都是父子相传.

It is not far from the house he lived in to the house I lived in. 从他居住的房子到我居住的房子并不远.

She went from house to house asking if anyone had seen the child. 她一家家去问是否有人见过这个小孩子.

(3) 但有时用不用冠词,与说话人的侧重点有关.比较并体会：

Then we transferredfrom a bus to a tram. 然后我们从公共汽车换成电车.

This is where we change from car to bus. 这就是我们从小汽车换乘公共汽车的地方.

(4) 在由from…to…构成的习语中,名词前通常是不用冠词的（见后面有关习语的用法归纳）.如：

He works from dawn till dusk. 他从天亮工作到天黑.

From time to time I still think of her. 我仍然不时地想起她.

He knows the subject from beginning to end. 这个专题他了如指掌.

The children were covered in mud from head to toe. 孩子们全身沾满了污泥.

She went from house to house asking if anyone had seen the child. 她一家家去问是否有人见过这个小孩子.

但也有些习语,用不用冠词均可以,如from (the) cradle to (the) grave（一辈子,从生到死）.如：

From (the) cradle to (the) grave, the car marks every rite of American passage. 在美国人的一生中,每一个重要阶段都有汽车的影子.

4. 关于与动名词的搭配

from…to…结构除通常与名词、代词、数词等搭配外,有时还可与动名词搭配.如：

He made a switch from publishing to teaching. 他由出版工作改做教学工作.

We are trying to shift the emphasis from curing illness to preventing it. 我们正在努力把工作重点从治疗疾病转为预防疾病.

He’s changed from being cynical about politics to being very interested in it. 他改变了对政治怀悲观的态度,而对其颇感兴趣.

注意,以下句子中的from…to…结构中,to为不定式符号,用于构成不定式表示结果或目的等.如：

She rose from her seat to protest. 她从座位上站起来提出抗议.

He rose from the ranks to become an officer. 他由士兵升为军官.

He dived from the bridge to rescue the drowning child. 他从桥上跳入水中去抢救那溺水儿童.

People came from far and near to hear the famous violinist. 人们从四面八方赶来听这位著名小提琴家的演奏.

5. 与动词vary, range等搭配

from…to…还经常与range, vary等表示“变化”“变动”的动词搭配使用,表示变化或变动的范围.如：

Dress sizes range from petite to extra large. 服装尺码从特小号到特大号不等.

His interests ranged from chess to canoeing. 他的爱好从下国际象棋到划独木舟,范围很广.

These fish vary in weight from 3 lb to 5 lb. 这些鱼的重量从3磅到5磅不等.

The heights of the plants vary from 8 cm to 20 cm. 这些植物的高度从8厘米到20厘米不等.

Her mood varied from optimism to extreme depression. 她的情绪由乐观一变而为极度消沉.

值得一提的是,from…to…与动词vary搭配使用时,其中的from…to…还经常用于连接两个相同的名词,强调变化或差异.如：

The weather varies from day to day. 天气一天天变化.

Test scores vary from school to school. 测试成绩各校不同.

Prices vary widely from shop to shop. 价格各个商店大不一样.

The treatment will vary from patient to patient. 治疗方法因人而异.

Levels of unemployment vary from region to region. 失业情形各地不同.

Social customs vary greatly from country to country. 社会习俗各国差别很大.

Medical treatment varies greatly from state to state. 医疗制度各州大不同一样.

The symptoms she suffered varied from month to month. 她的症状每个月都不同.

Office hours vary from company to company and country to country. 因公司、国家不同,办公时间也有所不同.

【注】lurch from one crisis / extreme etc to another: also lurch from crisis to crisis

比较以下相似表达：

Salary scales vary between states. 工资高低各州不同.

Salary scales vary from state to state. 工资高低一个州与另一州不同.

Salary scales vary according to state. 工资高低视所在的州有报不同.

Salary scales vary with each state. 工资高低各个州不同.

6. 用于 from one…to…结构

from one…to another

主要用于谈论三者或三者以上的情况,大意为“从一个……到另一个……”,具体翻译时需视句子语境而定.如：

She skipped from one subject to another. 她讲得没有条理,东拉西扯.

She spends the day rushing from one meeting to another. 她成天在会场之间奔波.

There are no mechanisms for transferring funds from one department to another. 基金无法从一部门转移至另一部门.

【注】该结构有时也可用于指谈论两者的情况,如下面一句摘自《朗文当代高级英语辞典》第4版的shift词条：

Joe listened, shifting uncomfortably from one foot to another. 乔听着,不安地把重心从一只脚转移到另一只脚.

from one…to the other

主要用于谈论两者的情况,意思是“从（两者中的）一个……到另一个……”.如：

The two cultures were so utterly disparate that she found it hard to adapt from one to the other. 两种文化迥然不同,她发现很难用一种去适应另一种.

from one…to the next

与from one…to another用法相惟,也主要用于谈论三者或三者以上的情况,表示“从一个……到下一个……”,具体翻译时需视句子语境而定.如：

His moods swung wildly from one day to the next. 他的情绪天天起伏很大.

You don’t know what his mood will be from one day to the next. 真说不上他的情绪今天怎样明天又怎样.

I couldn’t understand his lecture because he kept jumping from one topic to the next. 我听不懂他的演讲,他总是从一项内容跳到另一项内容.

Statistical anomalies can make it difficult to compare economic data from one year to the next. 统计数字的不规则,会使某一年的经济资料很难与下一年相比较.

7. 用于某些习惯搭配

from beginning to end 从头到尾

I’ve read the book from beginning to end. 我把这本书从头到尾看完了.

The argument was shallow from beginning to end. 那次辩论从头到尾都很肤浅.

from bad to worse 越来越糟

Things are going from bad to worse. 事态越来越糟了.

His business is going from bad to worse. 他的生意每况愈下.

from cover to cover 从头至尾地

八、from the distance还是from a distance？

from the distance释义：

从远处

例句：

From the distance came soft music.

远处传来柔和的乐曲声。

from a distance释义：

从远处；隔开一段距离

例句：

Even from a distance, the effect of his fox costume was stunning.

即使从远处看，他的狐装造型也非常漂亮。

九、away from与from区别？

away from

远离常见释义

英[əˈweɪ frəm]

美[əˈweɪ frəm]

prep.

离开;

例句

It was heaven being away from the office for a week.

一个星期远离办公室真是快活极了。

from

从…起常见释义

英[frəm]

美[frəm]

prep.

(表示起始点)从…起，始于;(表示开始的时间)从…开始;(表示由某人发出或给出)寄自，得自;（表示来源）来自，源于，出自，从…来;（表示所用的原料）由…（制成）;离;从;（表示幅度或范围）从…（到）;（表示改变前的状态或形式）从…（到）;（表示防止）使免遭，使免受;（表示原因）由于，因为;根据，从…来看;（区别二者时用）与…（不同）;

例句

Charlie called from the living room. "Bella?"

十、in from of和in the from of的区别？

你好，你要问的应该是in front of和in the front of的区别。两者都是在……之前。

但是，前者是在这个物体外部的前方，eg:There is a tree in front of the classroom.教室(外)前边有棵树。

后者是在物体内部的前方，eg: There is a blackboard in the front of the classroom.教室(内)前边有块黑板。

祝你学习顺利哈。