How to Use jq?

jq is a powerful command-line XML processor that allows developers to easily filter, map, and transform XML data just like using sed, awk, and grep to process text. jq offers many advantages for processing XML data:

  • Lightweight and efficient: Process XML without loading the entire dataset
  • Powerful query language: Support complex data transformation and filtering
  • High performance: Maintain fast response even when processing large XML files
  • Rich community support: Complete documentation and numerous examples

Typical application scenarios include:

  • API response processing: Extract relevant data from complex API responses
  • Log analysis: Parse and filter XML formatted log files
  • Data cleaning: Preprocess XML data for data analysis
  • Configuration transformation: Batch modify XML configuration files

Using jq in XML For You

XML For You supports online jq processing, just follow these steps:

  1. Paste the XML string into the left editor;
  2. Click "Search Command" at the top, find "Show jq input box", and a jq input box will appear at the bottom after clicking;
  3. Enter a jq expression (for example: .[] | select(.status == "active")) to automatically execute the jq command;
  4. You can view the results in the right editor;
  5. When you need to edit multiple times, you can quickly swap the text in the left and right editors with the Ctrl+Enter shortcut;
Using jq in XML For You

Common jq Command Examples

Basic Filtering

Extract specific fields from an XML object:

# Get all usernames in an array
.[] | .name

# Extract nested fields
.users[] | {id: .user_id, name: .profile.name}

Data Transformation

Modify the XML structure and values:

# Add a new field
.[] | . + {full_name: (.first_name + " " + .last_name)}

# Transform values
.items[] | {product: .name, price: (.price * 1.1)} # Add 10% tax

Conditional Selection

Filter data based on conditions:

# Select active users
.users[] | select(.status == "active" and .login_count > 5)

# Exclude null values
.data[] | select(.value != null and .value != "")

jq Advanced Techniques

Array Operations

# Get unique values
.[] | .category | unique

# Count the number of elements
.[] | .tags | length as $len | {item: ., tag_count:$len}

Complex Transformations

# Group items by category
.group_by(.category)[] | {categoryKey: .[].category, items:.}

# Flatten nested arrays
.recursive_field[] | .[] | {id: .id, value: .data.value}