Import CSV - This workflow will act as a meta workflow trying to answer questions about importing data from CSV and Text files One of the most frequently asked questions is the one how to import data from CSV and Text files under various circumsatnces. Often these files are messy with unbalanced quotes and column separators that would also appear in the data. Best advise would be to avoid CSV at all and resort to formats the would preserve the column types and formats like Parquet, ORC, ARFF or even H2 or SQLite - but often this is not possible The (new) CSV Reader should be the first stop https://hub.knime.com/knime/extensions/org.knime.features.base/latest/org.knime.base.node.io.filehandling.csv.reader.CSVTableReaderNodeFactory => please also note that you can configure a lot of settings like "Support changing file schemas" if your CSV structure does change or force data types https://hub.knime.com/knime/extensions/org.knime.features.base/latest/org.knime.base.node.io.filehandling.csv.reader.CSVTableReaderNodeFactory#relatedworkflowsnodes use R to read and write custom CSV files and read them back with different nodes https://hub.knime.com/mlauber71/spaces/Public/latest/kn_example_r_csv_read_write => also on the right side a collection of several nodes to import CSV and TXT files Force all columns to be read as strings (use KNIME nodes only) https://hub.knime.com/mlauber71/spaces/Public/latest/kn_example_csv_import_force_all_string_pure_knime Demonstrates how to import several CSV files with the new CSV reader from sub folders at once https://hub.knime.com/mlauber71/spaces/Public/latest/kn_example_csv_import_multiple_csv_types ------------- Often if everything else fails R's "Readr" package might still be able to help you use R library(readr) to read (messy) CSV file into KNIME https://hub.knime.com/mlauber71/spaces/Public/latest/kn_example_r_read_single_csv_file => also export files to ARFF, Parquet and SQLite (with and without R) to preserve column types import 'dirty' CSV files with the help of R's readr https://hub.knime.com/mlauber71/spaces/Public/latest/kn_example_r_import_csv_r_readr Force R’s readr to import all columns of a messy CSV file as strings - allow changing table structures https://hub.knime.com/mlauber71/spaces/Public/latest/kn_example_r_import_csv_messy_loop_force_all_string Import CSV with non-printable UNICODE characters https://forum.knime.com/t/csv-writer-problem/28064/9?u=mlauber71 https://hub.knime.com/mlauber71/spaces/Public/latest/forum/kn_forum_28064_r_import_csv_r_readr_strange_charaters ------------- CSV's can be used to append data to an existing file without having to reload it again Download data from a database in chunks and append them to an CSV file https://hub.knime.com/mlauber71/spaces/Public/latest/kn_example_write_csv_loop_chunks/m_001_write_csv_loop_chunks ------------- You can also move CSV files around copy files to two target folders using local URI strings - the basic version https://hub.knime.com/mlauber71/spaces/Public/latest/kn_example_move_csv_files_basic copy files to two target folders using local URI strings https://hub.knime.com/mlauber71/spaces/Public/latest/kn_example_move_csv_files ------------- And you often combine CSV files with other formats like MS Access, Excel and Big Data systems Export huge MS sql table to csv without fetching all records together https://hub.knime.com/mlauber71/spaces/Public/latest/forum/kn_example_huge_db_to_csv/m_001_write_csv_41 CSV files from subfolders to xlsx sheets https://hub.knime.com/mlauber71/spaces/Public/latest/forum/kn_example_csv_to_excel/m_001_import KNIME and Hive - load multiple CSV files at once via external table https://hub.knime.com/mlauber71/spaces/Public/latest/kn_example_bigdata_hive_csv_loader/m_001_import_hive_csv
Used extensions & nodes
All required extensions are part of the default installation of KNIME Analytics Platform version 4.4.1
No known nodes available
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