How can i read csv files

DictReader file. Previous Working with csv files in Python. Recommended Articles. Article Contributed By :. Easy Normal Medium Hard Expert. Writing code in comment? Please use ide. Load Comments. What's New. Most popular in Python. More related articles in Python. Python program to convert a list to string Iterate over a list in Python Reading and Writing to text files in Python Python String replace.

We use cookies to ensure you have the best browsing experience on our website. This practice is acceptable when dealing with one or two files. But it will make the code more redundant and ugly once we start working with multiple CSV files with similar formats. As a solution to this, the csv module offers dialect as an optional parameter. Dialect helps in grouping together many specific formatting patterns like delimiter , skipinitialspace , quoting , escapechar into a single dialect name. It can then be passed as a parameter to multiple writer or reader instances.

Instead of passing three individual formatting patterns, let's look at how to use dialects to read this file. From this example, we can see that the csv. It has the following syntax:. The custom dialect requires a name in the form of a string. Other specifications can be done either by passing a sub-class of Dialect class, or by individual formatting patterns as shown in the example. The advantage of using dialect is that it makes the program more modular. Notice that we can reuse 'myDialect' to open other files without having to re-specify the CSV format.

The objects of a csv. DictReader class can be used to read a CSV file as a dictionary. As we can see, the entries of the first row are the dictionary keys. And, the entries in the other rows are the dictionary values. DictReader object. The object can be iterated over using a for loop.

The csv. DictReader returned an OrderedDict type for each row. That's why we used dict to convert each row to a dictionary. Notice that we have explicitly used the dict method to create dictionaries inside the for loop. Note : Starting from Python 3. Because CSV files use a special formatting, the only way to ensure that they display correctly is to import them using a special process. Open a blank worksheet in Excel.

Click the Data tab and select From Text. Select the CSV file and click Import. Select "Delimited" and choose Next. Check the box next to "Comma" and click Next. Select all of the columns in the preview. Click Finish. Did this summary help you? Yes No. Log in Social login does not work in incognito and private browsers. Please log in with your username or email to continue. No account yet? Create an account. Edit this Article.

We use cookies to make wikiHow great. By using our site, you agree to our cookie policy. Cookie Settings. Learn why people trust wikiHow. Download Article Explore this Article methods. Related Articles. Article Summary. Method 1. Open Microsoft Excel on your computer. However, this may not display the data in the CSV as intended. Follow this method to properly open your CSV file without losing formatting and other data. Click Blank Worksheet. If it is set to 'ignore' , extra values in the dictionary are ignored.

Any other optional or keyword arguments are passed to the underlying writer instance. Note that unlike the DictReader class, the fieldnames parameter of the DictWriter class is not optional.

The Dialect class is a container class whose attributes contain information for how to handle doublequotes, whitespace, delimiters, etc. Dialect instances define how reader and writer instances behave. The excel class defines the usual properties of an Excel-generated CSV file.

It is registered with the dialect name 'excel'. It is registered with the dialect name 'excel-tab'. It is registered with the dialect name 'unix'. The Sniffer class is used to deduce the format of a CSV file.

The Sniffer class provides two methods:. Analyze the given sample and return a Dialect subclass reflecting the parameters found.

If the optional delimiters parameter is given, it is interpreted as a string containing possible valid delimiter characters. Analyze the sample text presumed to be in CSV format and return True if the first row appears to be a series of column headers.

Inspecting each column, one of two key criteria will be considered to estimate if the sample contains a header:. An example for Sniffer use:. The csv module defines the following constants:.

Instructs writer objects to quote all fields. Instructs writer objects to only quote those fields which contain special characters such as delimiter , quotechar or any of the characters in lineterminator.

Instructs writer objects to quote all non-numeric fields. Instructs writer objects to never quote fields. When the current delimiter occurs in output data it is preceded by the current escapechar character.

If escapechar is not set, the writer will raise Error if any characters that require escaping are encountered. Instructs reader to perform no special processing of quote characters. The csv module defines the following exception:. To make it easier to specify the format of input and output records, specific formatting parameters are grouped together into dialects.

A dialect is a subclass of the Dialect class having a set of specific methods and a single validate method. When creating reader or writer objects, the programmer can specify a string or a subclass of the Dialect class as the dialect parameter.