What is the difference between reading and writing data

It deletes all the content of the file and keeps the point at the beginning of the file. It deletes all the old contents from the text file and save new text inside the file. Welcome to CSEstack.

We are learning File Handling in Python. Aniruddha Chaudhari. I am complete Python Nut, love Linux and vim as an editor. I keep sharing my coding knowledge and my own experience on CSEstack. Your name can also be listed here. Got a tip? Submit it here to become an CSEstack author.

Thanks a lot, Aniruddha! Examples of bad pie charts: Figure 1. Elements in Martian soil. It is also hard to distinguish fifteen colors when comparing the pie chart to the color coded key.

Figure 2. Leisure activities of Venusian teenagers. The chart shows the relative proportion of five leisure activities of Venusian teenagers tanning, trips to Mars, reading, messing with satellites, and stealing Earth cable. Bar graphs are also used to display proportions. In particular, they are useful for showing the relationship between independent and dependent variables, where the independent variables are discrete often nominal categories. Some examples are occupation, gender, and species.

Bar graphs can be vertical or horizontal. In a vertical bar graph the independent variable is shown on the x axis left to right and the dependent variable on the y axis up and down. In a horizontal one, the dependent variable will be shown on the horizontal x axis, the independent on the vertical y axis. The scale and origin of the graph should be meaningful. If the dependent numeric variable has a natural zero point, it is commonly used as a point of origin for the bar chart.

However, zero is not always the best choice. You should experiment with both origin and scale to best show the relevant trends in your data without misleading the viewer in terms of the strength or extent of those trends.

Example of a bar graph: Figure 3. Genders of spaceship crew members in popular television series. Because the television series are arranged chronologically on the x-axis, the graph can also be used to look for trends in these numbers over time. Although the number of crew members for each show is similar ranging from 9 to 11 , the proportion of female and male crew members varies. Star Trek has half as many female crew members as male crew members 3 and 6, respectively , Battlestar has fewer than one-fourth as many female crew members as male crew members 2 and 9, respectively , Star Trek: TNG has four female crew members and six male crew members, Stargate SG-1 has less than one-half as many female crew members as male crew members 3 and 7, respectively , and Firefly has four female and five male crew members.

Frequency histograms are a special type of bar graph that show the relationship between independent and dependent variables, where the independent variable is continuous, rather than discrete. This means that each bar represents a range of values, rather than a single observation.

The dependent variables in a histogram are always numeric, but may be absolute counts or relative percentages. Frequency histograms are good for describing populations—examples include the distribution of exam scores for students in a class or the age distribution of the people living in Chapel Hill.

Scatter plots are another way to illustrate the relationship between two variables. In this case, data are displayed as points in an x,y coordinate system, where each point represents one observation along two axes of variation. Often, scatter plots are used to illustrate correlation between two variables—as one variable increases, the other increases positive correlation or decreases negative correlation.

However, correlation does not necessarily imply that changes in one variable cause changes in the other. For instance, a third, unplotted variable may be causing both. In other words, scatter plots can be used to graph one independent and one dependent variable, or they can be used to plot two independent variables. In cases where one variable is dependent on another for example, height depends partly on age , plot the independent variable on the horizontal x axis, and the dependent variable on the vertical y axis.

In addition to correlation a linear relationship , scatter plots can be used to plot non-linear relationships between variables. Example of a scatter plot: Figure 4. The effect of weather on UFO sightings. The scatter plot shows the relationship between temperature x-axis, independent variable and the number of UFO sightings y-axis, dependent variable for 53 separate data points.

It appears that the number of sightings tends to increase as temperature increases, though there are many cases where only a few sightings occur at high temperatures.

Line graphs are similar to scatter plots in that they display data along two axes of variation. Line graphs, however, plot a series of related values that depict a change in one variable as a function of another, for example, world population dependent over time independent. Line graphs are similar to bar graphs, but are better at showing the rate of change between two points. Line graphs can also be used to compare multiple dependent variables by plotting multiple lines on the same graph.

Figure 5. Age of the actor of each Doctor Who regeneration The line graph shows the age in years of the actor of each Doctor Who regeneration for the first through the eleventh regeneration. The ages range from a maximum of about 55 in the first regeneration to a minimum of about 25 in the eleventh regeneration. There is a downward trend in the age of the actors over the course of the eleven regenerations.

Strive for simplicity. Your data will be complex. Your job and the job of your graph is to communicate the most important thing about the data.

Think of graphs like you think of paragraphs—if you have several important things to say about your data, make several graphs, each of which highlights one important point you want to make.

Strive for clarity. The main two language skills used in written language is reading and writing skills. Written language is not transient like spoken language; it tends to be permanent since there are written records of it. Once you have written something, it is not very easy to change it.

Another interesting thing about written language is that the reader and writer are usually communicating across time and space, unlike in spoken language. Written language is typically more formal, complex and intricate than spoken language. It may contain longer sentences in complex tenses. However, some forms of written language like instant messages and informal letters are closer to spoken language.

Written language can make use of features like punctuation , headings, layouts, colors, etc. Since written language does not receive immediate feedback, it should be very clear and unambiguous. Spoken Language involves speaking and listening skills. Written Language involves reading and writing skills. Spoken Language is older than written language.

Written Language is not as old as the spoken language.