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Python逐行读取文件内容

流过昼夜 提交于 2020-02-12 01:05:35
1. 读取文本文件 代码: [python] view plain copy f = open( 'test.txt', 'r') print f.read() f.seek( 0) print f.read( 14) f.seek( 0) print f.readline() print f.readline() f.seek( 0) print f.readlines() f.seek( 0) for line in f: print line, f.close() 运行结果: root@he-desktop:~/python/example# python read_txt.py 第一行 第二行 第三行 第一行 第 第一行 第二行 ['\xe7\xac\xac\xe4\xb8\x80\xe8\xa1\x8c\n', '\xe7\xac\xac\xe4\xba\x8c\xe8\xa1\x8c\n', '\xe7\xac\xac\xe4\xb8\x89\xe8\xa1\x8c\n'] 第一行 第二行 第三行 open的第二个参数: r,读取模式 w,写入模式 a,追加模式 r+,读写模式 read()表示读取到文件尾,size表示读取大小。 seek(0)表示跳到文件开始位置。 readline()逐行读取文本文件。 readlines()读取所有行到列表中

python 逐行读取文本

青春壹個敷衍的年華 提交于 2020-02-12 01:04:43
f = open("foo.txt") # 返回一个文件对象line = f.readline() # 调用文件的 readline()方法while line: print line, # 后面跟 ',' 将忽略换行符 # print(line, end = '')   # 在 Python 3中使用 line = f.readline()f.close() 也可以写成以下更简洁的形式 for line in open("foo.txt"): print line, 更详细的文件按行读取操作可以参考: http://www.cnblogs.com/xuxn/archive/2011/07/27/read-a-file-with-python.html 1. 最基本的读文件方法:?# File: readline-example-1.py file = open("sample.txt") while 1: line = file.readline() if not line: break pass # do something  一行一行得从文件读数据,显然比较慢;不过很省内存。  在我的机器上读10M的sample.txt文件,每秒大约读32000行2. 用fileinput模块?# File: readline-example-2.py import fileinput

leetcode解题之第十行

ε祈祈猫儿з 提交于 2020-02-10 12:55:25
给定一个文本文件 file.txt,请只打印这个文件中的第十行。 示例: 假设 file . txt 有如下内容: Line 1 Line 2 Line 3 Line 4 Line 5 Line 6 Line 7 Line 8 Line 9 Line 10 你的脚本应当显示第十行: Line 10 说明: 如果文件少于十行,你应当输出什么? 至少有三种不同的解法,请尝试尽可能多的方法来解题。 来源:力扣(LeetCode) 链接:https://leetcode-cn.com/problems/tenth-line 著作权归领扣网络所有。商业转载请联系官方授权,非商业转载请注明出处。 学习脚本 awk 'NR == 10' file . txt 参考 awk指令用法 来源: CSDN 作者: l888c 链接: https://blog.csdn.net/l888c/article/details/104245417

Check is a point (x,y) is between two points drawn on a straight line

ぃ、小莉子 提交于 2020-02-09 02:39:32
问题 I have drawn a line between two points A(x,y)---B(x,y) Now I have a third point C(x,y). I want to know that if C lies on the line which is drawn between A and B. I want to do it in java language. I have found couple of answers similar to this. But, all have some problems and no one is perfect. 回答1: if (distance(A, C) + distance(B, C) == distance(A, B)) return true; // C is on the line. return false; // C is not on the line. or just: return distance(A, C) + distance(B, C) == distance(A, B);

SQL - ORA-00911 - Invalid Character while trying to insert records

十年热恋 提交于 2020-02-07 04:07:46
问题 Oracle Live SQL. I am trying to insert records for a table. The table goes through just fine but in each line of records, I am apparently entering some invalid characters. Of course, this is an extremely vague error. I don't know what's wrong. I've tried changing the date values, tried removing values individually, but no matter what I get the same error. CREATE TABLE Employee_Information ( employee varchar2(25) NOT NULL, Address varchar2(50) NOT NULL, Phone_number CHAR(10) NOT NULL, Hire

SQL - ORA-00911 - Invalid Character while trying to insert records

喜你入骨 提交于 2020-02-07 04:07:05
问题 Oracle Live SQL. I am trying to insert records for a table. The table goes through just fine but in each line of records, I am apparently entering some invalid characters. Of course, this is an extremely vague error. I don't know what's wrong. I've tried changing the date values, tried removing values individually, but no matter what I get the same error. CREATE TABLE Employee_Information ( employee varchar2(25) NOT NULL, Address varchar2(50) NOT NULL, Phone_number CHAR(10) NOT NULL, Hire

Tips--Anaconda安装TensorFlow报错ImportError: DLL load failed

廉价感情. 提交于 2020-02-05 02:27:47
在Anaconda中安装TensorFlow时,需要运行命令: pip install tensorflow 安装成功之后,在python命令行中输入: import tensorflow as tf 时会报错: Traceback ( most recent call last ) : File "C:\Users\Ethan\.conda\envs\tensorflow\lib\site-packages\tensorflow_core\python\pywrap_tensorflow.py" , line 58, in < module > from tensorflow.python.pywrap_tensorflow_internal import * File "C:\Users\Ethan\.conda\envs\tensorflow\lib\site-packages\tensorflow_core\python\pywrap_tensorflow_internal.py" , line 28, in < module > _pywrap_tensorflow_internal = swig_import_helper ( ) File "C:\Users\Ethan\.conda\envs\tensorflow\lib\site-packages

图及可视化

心不动则不痛 提交于 2020-02-03 20:29:54
各种线图: import mpf as mpf import numpy as np import matplotlib as mpl import matplotlib.pyplot as plt from matplotlib.patches import Polygon # import matplotlib.finance as mpf from mpl_toolkits.mplot3d import Axes3D ''' axex: 设置坐标轴边界和表面的颜色、坐标刻度值大小和网格的显示 backend: 设置目标暑促TkAgg和GTKAgg figure: 控制dpi、边界颜色、图形大小、和子区( subplot)设置 grid: 设置网格颜色和线性 legend: 设置图例和其中的文本的显示 line: 设置线条(颜色、线型、宽度等)和标记 patch: 是填充2D空间的图形对象,如多边形和圆。控制线宽、颜色和抗锯齿设置等。 savefig: 可以对保存的图形进行单独设置。例如,设置渲染的文件的背景为白色。 verbose: 设置matplotlib在执行期间信息输出,如silent、helpful、debug和debug-annoying。 xticks和yticks: 为x,y轴的主刻度和次刻度设置颜色、大小、方向,以及标签大小。 plt.figure

Print specific line in a .txt file in Python?

自闭症网瘾萝莉.ら 提交于 2020-02-03 01:26:07
问题 I have got a .txt file that contains a lot of lines. I would like my program to ask me what line I would like to print and then print it into the python shell. The .txt file is called packages.txt. 回答1: If you don't want to read in the entire file upfront, you could simply iterate until you find the line number: with open('packages.txt') as f: for i, line in enumerate(f, 1): if i == num: break print line Or you could use itertools.islice() to slice out the desired line (this is slightly hacky

Draw lines on a PictureBox

烈酒焚心 提交于 2020-02-02 04:08:13
问题 My question is related to Stack Overflow question Draw lines on a picturebox using mouse clicks in C# , but when the mouse button is up, the drawn line disappears. How do I fix this? private void GainBox_MouseDn(object sender, MouseEventArgs e) { mouse_dn = true; } private void GainBox_MouseMv(object sender, MouseEventArgs e) { //Line drawn from lookup table if (mouse_dn) { img = new Bitmap(256, 256); //Get the coordinates (x, y) for line from lookup table. for (x = x1; x < x2; x++) img